Agilent 86120C Multi-Wavelength Meter User’s Guide sA
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The Agilent 86120C—At a Glance The Agilent 86120C—At a Glance The Agilent 86120C Multi- Wavelength Meter measures the wavelength and optical power of laser light in the 1270–1650 wavelength range. Because the Agilent 86120C simultaneously measures multiple laser lines, you can characterize wavelength- division- multiplexed (WDM) systems and the multiple lines of Fabry- Perot lasers. NOTE The front-panel OPTICAL INPUT connector uses a single-mode input fiber.
The Agilent 86120C—At a Glance In addition to these measurements, a “power bar” is displayed that shows power changes like a traditional analog meter. You can see the power bar shown in the following figure of the Agilent 86120C’s display. CAUTION The input circuitry of the Agilent 86120C can be damaged when total input power levels exceed +18 dBm. To prevent input damage, this specified level must not be exceeded.
The Agilent 86120C—At a Glance Measurement accuracy—it’s up to you! Fiber-optic connectors are easily damaged when connected to dirty or damaged cables and accessories. The Agilent 86120C’s front-panel INPUT connector is no exception. When you use improper cleaning and handling techniques, you risk expensive instrument repairs, damaged cables, and compromised measurements. Before you connect any fiber-optic cable to the Agilent 86120C, refer to “Cleaning Connections for Accurate Measurements” on page 2-40.
General Safety Considerations General Safety Considerations This product has been designed and tested in accordance with IEC 61010- 1, and has been supplied in a safe condition. The instruction documentation contains information and warnings which must be followed by the user to ensure safe operation and to maintain the product in a safe condition. Laser Classification: This product is classified according to IEC 60825- 1.
General Safety Considerations WA R N I N G If this instrument is not used as specified, the protection provided by the equipment could be impaired. This instrument must be used in a normal condition (in which all means for protection are intact) only. WA R N I N G No operator serviceable parts inside. Refer servicing to qualified personnel. To prevent electrical shock, do not remove covers. WA R N I N G To prevent electrical shock, disconnect the Agilent 86120C from mains before cleaning.
General Safety Considerations CAUTION This product complies with Overvoltage Category II and Pollution Degree 2. CAUTION VENTILATION REQUIREMENTS: When installing the product in a cabinet, the convection into and out of the product must not be restricted. The ambient temperature (outside the cabinet) must be less than the maximum operating temperature of the product by 4°C for every 100 watts dissipated in the cabinet.
Contents The Agilent 86120C—At a Glance iii General Safety Considerations vi 1 Getting Started Step 1. Inspect the Shipment 4 Step 2. Connect the Line-Power Cable 5 Step 3. Connect a Printer 6 Step 4. Turn on the Agilent 86120C 7 Step 5. Enter Your Elevation 8 Step 6. Select Medium for Wavelength Values 9 Step 7.
Contents 4 Programming Commands Common Commands 3 Measurement Instructions 15 CALCulate1 Subsystem 25 CALCulate2 Subsystem 31 CALCulate3 Subsystem 44 CONFigure Measurement Instruction 74 DISPlay Subsystem 75 FETCh Measurement Instruction 79 HCOPy Subsystem 80 MEASure Measurement Instruction 81 READ Measurement Instruction 82 SENSe Subsystem 83 STATus Subsystem 90 SYSTem Subsystem 97 TRIGger Subsystem 103 UNIT Subsystem 107 5 Performance Tests Test 1. Absolute Wavelength Accuracy 3 Test 2.
Contents Menu Maps 4 Error Messages 11 Front-Panel Fiber-Optic Adapters 17 Power Cords 18 Agilent Technologies Service Offices 18 Contents-3
1 Step 1. Inspect the Shipment 1- 4 Step 2. Connect the Line- Power Cable 1- 5 Step 3. Connect a Printer 1- 6 Step 4. Turn on the Agilent 86120C 1- 7 Step 5. Enter Your Elevation 1- 8 Step 6. Select Medium for Wavelength Values Step 7.
Getting Started Getting Started Getting Started The instructions in this chapter show you how to install your Agilent 86120C. You should be able to finish these procedures in about ten to twenty minutes. After you’ve completed this chapter, continue with Chapter 2, “Making Measurements”. Refer to Chapter 6, “Specifications and Regulatory Information” for information on operating conditions such as temperature. If you should ever need to clean the cabinet, use a damp cloth only.
Getting Started Getting Started Measurement accuracy—it’s up to you! Fiber-optic connectors are easily damaged when connected to dirty or damaged cables and accessories. The Agilent 86120C’s front-panel INPUT connector is no exception. When you use improper cleaning and handling techniques, you risk expensive instrument repairs, damaged cables, and compromised measurements.
Getting Started Step 1. Inspect the Shipment Step 1. Inspect the Shipment 1 Verify that all system components ordered have arrived by comparing the shipping forms to the original purchase order. Inspect all shipping containers. If your shipment is damaged or incomplete, save the packing materials and notify both the shipping carrier and the nearest Agilent Technologies sales and service office.
Getting Started Step 2. Connect the Line-Power Cable Step 2. Connect the Line- Power Cable WA R N I N G This is a Safety Class I Product (provided with protective earth). The mains plug shall only be inserted in a socket outlet provided with a protective earth contact. Any interruption of the protective conductor inside or outside of the instrument is likely to make the instrument dangerous. Intentional interruption is prohibited.
Getting Started Step 3. Connect a Printer 3 Connect the other end of the line- power cord to the power receptacle. Various power cables are available to connect the Agilent 86120C to ac power outlets unique to specific geographic areas. The cable appropriate for the area to which the Agilent 86120C is originally shipped is included with the unit. The cable shipped with the instrument also has a right- angle connector so that the Agilent 86120C can be used while sitting on its rear feet.
Getting Started Step 4. Turn on the Agilent 86120C Step 4. Turn on the Agilent 86120C 1 Press the front- panel LINE key. After approximately 20 seconds, the display should look similar to the figure below. The front- panel LINE switch disconnects the mains circuits from the mains supply after the EMC filters and before other parts of the instrument.
Getting Started Step 5. Enter Your Elevation Step 5. Enter Your Elevation In order for your Agilent 86120C to accurately measure wavelengths and meet its published specifications, you must enter the elevation where you will be performing your measurements. 1 Press the Setup key. 2 Press the MORE softkey. 3 Press the CAL softkey. 4 Press ELEV. 5 Use the and softkeys to enter the elevation in meters. Entries jump in 500 meter steps from 0 m to 5000 m.
Getting Started Step 6. Select Medium for Wavelength Values Step 6. Select Medium for Wavelength Values Because wavelength varies with the material that the light passes through, the Agilent 86120C offers wavelength measurements in two mediums: vacuum and standard air. 1 Press the Setup key. 2 Press the MORE softkey. 3 Press the CAL softkey. 4 Make the following selection: • Press VACUUM for wavelength readings in a vacuum. • Press STD AIR for wavelength readings in standard air.
Getting Started Step 7. Turn Off Wavelength Limiting Step 7. Turn Off Wavelength Limiting The instrument’s Preset key sets the entire Agilent 86120C wavelength range of 1270–1650 nm. If a user- defined wavelength range limit was set using WL LIM, the following procedure will ensure that responses across the full wavelength are measured by returning the instrument to its preset state. 1 Press the Setup key. 2 Press the WL LIM softkey. 3 Press LIM OFF to remove the limits on wavelength range.
Getting Started Returning the Instrument for Service Returning the Instrument for Service The instructions in this section show you how to properly return the instrument for repair or calibration. Always call the Agilent Technologies Instrument Support Center first to initiate service before returning your instrument to a service office. This ensures that the repair (or calibration) can be properly tracked and that your instrument will be returned to you as quickly as possible.
Getting Started Returning the Instrument for Service Preparing the instrument for shipping 1 Write a complete description of the failure and attach it to the instrument. Include any specific performance details related to the problem. The following information should be returned with the instrument. • Type of service required. • Date instrument was returned for repair. • Description of the problem: • Whether problem is constant or intermittent. • Whether instrument is temperature-sensitive.
Getting Started Returning the Instrument for Service 3 Pack the instrument in the original shipping containers. Original materials are available through any Agilent Technologies office. Or, use the following guidelines: • Wrap the instrument in antistatic plastic to reduce the possibility of damage caused by electrostatic discharge. • For instruments weighing less than 54 kg (120 lb), use a doublewalled, corrugated cardboard carton of 159 kg (350 lb) test strength.
Getting Started Returning the Instrument for Service 1-14
Getting Started Returning the Instrument for Service 1-15
2 Measuring Wavelength and Power 2- 3 Peak WL mode 2-4 List by WL or Power modes 2-6 Total power and average wavelength 2-7 Limiting the wavelength measurement range 2-8 Measuring broadband devices and chirped lasers 2-9 Graphical display of optical power spectrum 2-10 Instrument states 2-11 Power bar 2-11 Changing the Units and Measurement Rate 2- 12 Displayed units 2-12 Measurement rate 2-13 Continuous or single measurements 2-14 Defining Laser- Line Peaks 2- 15 Measuring Laser Separation 2- 18 Channel se
Making Measurements Making Measurements Making Measurements In this chapter, you’ll learn how to make a variety of fast, accurate measurements. As you perform these measurements, keep in mind the following points: • 1270–1650 maximum input wavelength range • +10 dBm maximum total displayed input power • Laser linewidths assumed to be less than 5 GHz • If you change the elevation where you will be using your Agilent 86120C, refer to “Calibrating Measurements” on page 2- 37.
Making Measurements Measuring Wavelength and Power Measuring Wavelength and Power This section gives you step- by- step instructions for measuring peak wavelength, average wavelength, peak power, and total input power. There are three display modes: • Peak wavelength • List- by- wavelength or power • Average wavelength and total power If the measured amplitudes are low, clean the front- panel OPTICAL INPUT connector.
Making Measurements Measuring Wavelength and Power Peak WL mode When Peak WL is pressed, the display shows the largest amplitude line in the spectrum. The word PEAK is shown on the screen. If multiple laser lines are present at the input, the number of lines located will be shown along the right side of the screen. In peak wavelength mode, the Agilent 86120C can measure up to 200 laser lines simultaneously. Figure 2-1.
Making Measurements Measuring Wavelength and Power 3 To move the cursor to view other signals, press: • PREV WL to select next (previous) shorter wavelength. • NEXT WL to select next longer wavelength. • PEAK to signal with greatest power. • PREV PK to select next lower power signal. • NEXT PK to select next higher power signal.
Making Measurements Measuring Wavelength and Power List by WL or Power modes In the list- by- wavelength or list- by- power modes, the measurements of five laser lines can be displayed at any one time. Use the and softkeys to move the cursor through the list of signals; the list can contain up to 200 entries. Press the SELECT key, and the display changes to peak wavelength mode with the signal at the cursor displayed.
Making Measurements Measuring Wavelength and Power Total power and average wavelength In the third available display mode, the Agilent 86120C displays the average wavelength as shown in the following figure. The displayed power level is the total input power to the instrument. It is the sum of the powers of each laser line; it is not a measure of the average power level of the laser lines.
Making Measurements Measuring Wavelength and Power The following equation shows how individual powers of laser lines are summed together to obtain the total power value: n P total = ∑P i i=1 where, n is the number of laser lines included in the measurement. Pi is the peak power of an individual laser line. Power units are in Watts (linear). To display average wavelength and total power • Press the Avg WL key.
Making Measurements Measuring Wavelength and Power Measuring broadband devices and chirped lasers When first turned on (or the green Preset key is pressed), the Agilent 86120C is configured to measure narrowband devices such as DFB lasers and modes of FP lasers. If you plan to measure broadband devices such as LEDs, optical filters, and chirped lasers, use the Setup menu first to reconfigure the instrument. When broadband devices are selected, the display shows the BROAD annotation on the screen.
Making Measurements Measuring Wavelength and Power Graphical display of optical power spectrum A graphical display of optical power versus wavelength is shown from the start wavelength value to the stop wavelength value. The start wavelength value is shown in the upper- left corner of the graphical display, and the stop wavelength value is shown in the upper- right corner of the graphical display. The power scale is a fixed dB scale, with +10 dBm at the display top and –53 dBm at the display bottom.
Making Measurements Measuring Wavelength and Power Instrument states Four different instrument states can be saved and recalled at a later time. The actual instrument conditions that are saved are identical to those saved from the previous state after power is turned on. These conditions are shown in Table 5- 22 on page 7- 2. If drift measurements or an application (such as signal- to- noise) is on when an instrument state is saved, it is off when that state is recalled.
Making Measurements Changing the Units and Measurement Rate Changing the Units and Measurement Rate This section includes step- by- step instructions for changing the units and measurement rate. This section includes: Displayed units 2- 12 Measurement rate 2- 13 Continuous or single measurements 2- 14 Displayed units As described below, it’s easy to change the wavelength and amplitude units. You can choose between the following units: Table 2-1.
Making Measurements Changing the Units and Measurement Rate 4 Press WL and select one of the following units. Then, press RETURN to complete your selection: • NM for nanometers • THZ for Tera Hertz • CM –1 for wave number 5 Press POWER and select one of the following units: • DBM for decibels relative to a milliwatt • MW for milliwatts • UW for microwatts Measurement rate Under normal operation, the Agilent 86120C makes a measurement and displays the results about once every second.
Making Measurements Changing the Units and Measurement Rate To change the measurement speed 1 Press the Setup key. 2 Press the MORE softkey. 3 Press the UPDATE softkey. 4 Select either NORMAL or FAST. Continuous or single measurements The Agilent 86120C continuously measures the input spectrum at the front- panel OPTICAL INPUT connector. Whenever measurements are being acquired, an asterisk (*) is displayed in the display’s upper- right corner.
Making Measurements Defining Laser-Line Peaks Defining Laser- Line Peaks The Agilent 86120C uses two rules to identify valid laser- line peaks. Understanding these rules is essential to getting the most from your measurements. For example, these rules allow you to “hide” AM modulation sidebands or locate laser lines with small amplitudes.
Making Measurements Defining Laser-Line Peaks Peak excursion The peak excursion defines the rise and fall in amplitude that must take place in order for a laser line to be recognized. The rise and fall can be out of the noise, or in the case of two closely spaced signals, out of the filter skirts of the adjacent signal. The peak excursion’s default value is 15 dB. Any laser line that rises by 15 dB and then falls by 15 dB passes the rule. You can set the peak excursion value from 1 to 30 dB.
Making Measurements Defining Laser-Line Peaks 3 Press PX EXC, and enter the peak excursion value. Use the softkey to select the digit that requires editing. Use the and softkeys to change the value. The peak excursion value can range from 1 to 30 dB. The default value is 15 dB. 4 Press RETURN. 5 Press PK THLD and then enter the peak threshold value. The peak threshold value can range from 0 to 40 dB. Setting this value to 0 dB ensures that only the peak wavelength is identified. The default value is 10 dB.
Making Measurements Measuring Laser Separation Measuring Laser Separation It is often important to measure the wavelength and power separation between multiple laser lines. This is especially true in wavelength- division- multiplexed (WDM) systems where channel spacing must be adhered to. The Agilent 86120C can display the wavelength and amplitude of any laser line relative to another.
Making Measurements Measuring Laser Separation Channel separation Suppose that you want to measure separation on a system having the spectrum shown in the following figure. The Agilent 86120C displays separation on this spectrum as shown in the following figure. Notice that the 1541.747 nm laser line is selected as the reference. It is shown in absolute units. The wavelengths and powers of the remaining responses are shown relative to this reference. For example, the first response is 2.
Making Measurements Measuring Laser Separation To measure channel separation 1 Press the front- panel Preset key. 2 Press List by WL. 3 Press the Delta On key. Use the Off key to turn off the measurement. 4 Select the type of separation to observe: • ∆ WL displays channel separation. • ∆ WL / ∆ PWR displays both channel separation and differences in power. 5 Use the and softkeys to select the reference laser line. 6 Press SELECT. Press SELECT at any time to select a new reference.
Making Measurements Measuring Laser Separation Measuring flatness You can use relative power measurements to measure flatness (preemphasis) in a WDM system. Simply select one carrier as the reference and measure the remaining carriers relative to the reference level. The power differences represent the system flatness. Press RESET to turn off the delta calculations so that all responses are shown in absolute wavelength and powers. To measure flatness 1 Press the front- panel Preset key.
Making Measurements Measuring Laser Drift Measuring Laser Drift In this section, you’ll learn how the Agilent 86120C can be used to monitor drift (changes to a laser’s wavelength and amplitude over time). Drift is measured simultaneously for every laser line that is identified at the input. The Agilent 86120C keeps track of each laser line’s initial, current, minimum, and maximum values and displays their differences relative to itself.
Making Measurements Measuring Laser Drift You can restart the drift measurement at any time by pressing the RESET softkey. All minimum and maximum values are reset to the reference values, and the Agilent 86120C begins to monitor drift from the current laser line values. Move the cursor up and down the listing to see the reference wavelength and power of each laser line.
Making Measurements Measuring Laser Drift maximum wavelength and maximum power may not have occurred simultaneously. Display shows absolute minimum values since the drift measurement was started. This measurement gives the shortest wavelength and smallest power measured. The laser line of interest may have since drifted to a greater value. Note that the minimum wavelength and minimum power may not have occurred simultaneously.
Making Measurements Measuring Signal-to-Noise Ratios Measuring Signal- to- Noise Ratios Signal- to- noise measurements provide a direct indication of system performance. Signal- to- noise measurements are especially important in WDM systems because there is a direct relation between signal- tonoise and bit error rate. The Agilent 86120C displays signal- to- noise measurements in the third column. For example, the selected signal in the following figure has a signal- to- noise ratio of 30.0 dB.
Making Measurements Measuring Signal-to-Noise Ratios Location of noise measurements Automatic interpolation When the signal- to- noise “auto” function is selected, the Agilent 86120C first determines the proximity of any adjacent signal. If the next closest signal is ≤200 GHz (approximately 1.6 nm at 1550 nm) away from the signal of interest, then the noise power is measured half way between the two channels and an equal distance to the other side of the signal of interest.
Making Measurements Measuring Signal-to-Noise Ratios Automatic interpolation User- entered wavelength When the signal- to- noise “user” function is selected, the Agilent 86120C uses only one wavelength to measure the noise power for all signals. This wavelength is set by the user and all signals are compared to the noise level at this wavelength to determine their corresponding signal- to- noise ratios.
Making Measurements Measuring Signal-to-Noise Ratios To measure signal- to- noise 1 Press the front- panel Preset key. 2 Press List by WL or List by Power. 3 Press Appl’s and then S/N. 4 To select the wavelength reference for measuring the noise, do the following steps: a Press WL REF, and • press AUTO to let the instrument interpolate the wavelength, or • press USER to select the last wavelength manually entered. b If you chose USER, you can specify the wavelength by pressing USER WL.
Making Measurements Measuring Signal-to-Noise Ratios with Averaging Measuring Signal- to- Noise Ratios with Averaging When the lasers being measured are modulated, especially with repetitive data formats such as SONET or PRBS, the noise floor is raised. Averaging reduces the noise floor and allows an improvement of greater than 10 dB in a signal- to- noise measurement. In general, averaging will decrease the noise floor caused by modulation until the true optical noise level is reached.
Making Measurements Measuring Signal-to-Noise Ratios with Averaging averages taken so far. The maximum number of averages is 900, the minimum number of averages is 10, and the default (Preset) value is 100 averages. A measurement with 100 averages takes about 2 minutes to complete. When the measurement is complete, the instrument switches to single measurement mode. Then, pressing the Cont key will start a completely new measurement.
Making Measurements Measuring Fabry-Perot (FP) Lasers Measuring Fabry- Perot (FP) Lasers The Agilent 86120C can perform several measurements on Fabry- Perot lasers including FWHM and mode spacing. The display shows the measurement results in the selected wavelength and amplitude units. In addition, the mode spacing measurement always shows results in frequency as well as the selected wavelength units. Refer to “Displayed units” on page 2- 12 to learn how to change the units.
Making Measurements Measuring Fabry-Perot (FP) Lasers Measurement Description FWHM FWHM (full width at half maximum) describes the spectral width of the half-power points of the laser, assuming a continuous, Gaussian power distribution. The half-power points are those where the power spectral density is one-half that of the peak amplitude of the computed Gaussian curve. FWHM = 2.355 σ where, σ is sigma as defined below. MEAN The wavelength representing the center of mass of selected peaks.
Making Measurements Measuring Fabry-Perot (FP) Lasers PWR The summation of the power in each of the selected peaks, or modes, that satisfy the peak-excursion and peak-threshold criteria. N Total Power = Σ Pi i =1 The peak excursion and peak threshold settings define the laser modes included in the measurement. Because the default peak excursion value is 10 dB, measurement results normally include all laser modes within 10 dB of the peak response.
Making Measurements Measuring Modulated Lasers Measuring Modulated Lasers A laser that is amplitude modulated at low frequencies (for example, modulated in the audio frequency range) can cause spurious wavelengths to be displayed below and above the correct wavelength. The power of these spurious wavelengths is below that of the correct wavelength. These spurious signals can be eliminated by decreasing the peak threshold. Refer to “Defining Laser- Line Peaks” on page 2- 15.
Making Measurements Measuring Modulated Lasers The graphical display is useful for locating these spurious wavelengths. Their amplitude will be below that of the correct wavelength and they will be broad, rounded peaks compared to the sharp peak of the correct wavelength. Use the Peak Threshold function to place the dotted line above the spurious peaks so they will not be displayed in the List by WL or List by Power table.
Making Measurements Measuring Total Power Greater than 10 dBm Measuring Total Power Greater than 10 dBm The maximum total power that can be measured by the Agilent 86120C is 10 dBm. However, with the addition of an external attenuator, more power can be applied. This may be necessary at the transmit end of a wavelength- division- multiplexed system where large signal levels are present.
Making Measurements Calibrating Measurements Calibrating Measurements The wavelength of light changes depending on the material that the light is passing through. To display meaningful wavelength measurements, the Agilent 86120C performs two steps: 1 Measures the wavelength in air. 2 Converts the wavelength to show values in either a vacuum or “standard air”. For example, a laser line with a wavelength of 1550.000 nm in a vacuum would have a wavelength in standard air of 1549.577 nm.
Making Measurements Calibrating Measurements To enter the elevation 1 Press the Setup key. 2 Press the MORE softkey. 3 Press the CAL softkey. 4 Press ELEV. 5 Use the and softkeys to enter the elevation in meters. Entries jump in 500 meter steps from 0 m to 5000 m. In order for the Agilent 86120C to meet its published specifications, the elevation value selected with the softkeys must be within 250 meters of the actual elevation. 6 Press RETURN to complete the entry.
Making Measurements Printing Measurement Results Printing Measurement Results Measurement results can be sent directly to a printer. Simply connect a compatible printer to the rear- panel PARALLEL PRINTER PORT connector. The output is ASCII text. An example of a compatible printer is Hewlett- Packard®’s LaserJet1 series printer. Be sure to use a parallel printer cable to connect the printer. The printer output is not a copy of the display.
Making Measurements Cleaning Connections for Accurate Measurements Cleaning Connections for Accurate Measurements Today, advances in measurement capabilities make connectors and connection techniques more important than ever. Damage to the connectors on calibration and verification devices, test ports, cables, and other devices can degrade measurement accuracy and damage instruments.
Making Measurements Cleaning Connections for Accurate Measurements • Is an instrument- grade connector with a precision core alignment required? • Is repeatability tolerance for reflection and loss important? Do your specifications take repeatability uncertainty into account? • Will a connector degrade the return loss too much, or will a fusion splice be required? For example, many DFB lasers cannot operate with reflections from connectors. Often as much as 90 dB isolation is needed. Figure 2-3.
Making Measurements Cleaning Connections for Accurate Measurements Figure 2-4. Universal adapters to Diamond HMS-10. The HMS- 10 encases the fiber within a soft nickel silver (Cu/Ni/Zn) center which is surrounded by a tough tungsten carbide casing, as shown in Figure 2- 5. Figure 2-5. Cross-section of the Diamond HMS-10 connector. The nickel silver allows an active centering process that permits the glass fiber to be moved to the desired position.
Making Measurements Cleaning Connections for Accurate Measurements The soft core, while allowing precise centering, is also the chief liability of the connector. The soft material is easily damaged. Care must be taken to minimize excessive scratching and wear. While minor wear is not a problem if the glass face is not affected, scratches or grit can cause the glass fiber to move out of alignment. Also, if unkeyed connectors are used, the nickel silver can be pushed onto the glass surface.
Making Measurements Cleaning Connections for Accurate Measurements Use the following guidelines to achieve the best possible performance when making measurements on a fiber- optic system: • Never use metal or sharp objects to clean a connector and never scrape the connector. • Avoid matching gel and oils. Figure 2-6. Clean, problem-free fiber end and ferrule. Figure 2-7. Dirty fiber end and ferrule from poor cleaning.
Making Measurements Cleaning Connections for Accurate Measurements Figure 2-8. Damage from improper cleaning. While these often work well on first insertion, they are great dirt magnets. The oil or gel grabs and holds grit that is then ground into the end of the fiber. Also, some early gels were designed for use with the FC, non- contacting connectors, using small glass spheres. When used with contacting connectors, these glass balls can scratch and pit the fiber.
Making Measurements Cleaning Connections for Accurate Measurements tor pressure. Also, if a piece of grit does happen to get by the cleaning procedure, the tighter connection is more likely to damage the glass. Tighten the connectors just until the two fibers touch. • Keep connectors covered when not in use. • Use fusion splices on the more permanent critical nodes. Choose the best connector possible. Replace connecting cables regularly.
Making Measurements Cleaning Connections for Accurate Measurements Visual inspection of fiber ends Visual inspection of fiber ends can be helpful. Contamination or imperfections on the cable end face can be detected as well as cracks or chips in the fiber itself. Use a microscope (100X to 200X magnification) to inspect the entire end face for contamination, raised metal, or dents in the metal as well as any other imperfections. Inspect the fiber for cracks and chips.
Making Measurements Cleaning Connections for Accurate Measurements CAUTION Agilent Technologies strongly recommends that index matching compounds not be applied to their instruments and accessories. Some compounds, such as gels, may be difficult to remove and can contain damaging particulates. If you think the use of such compounds is necessary, refer to the compound manufacturer for information on application and cleaning procedures. Table 2-2.
Making Measurements Cleaning Connections for Accurate Measurements paper. 4 Clean the fiber end with the swab or lens paper. Do not scrub during this initial cleaning because grit can be caught in the swab and become a gouging element. 5 Immediately dry the fiber end with a clean, dry, lint- free cotton swab or lens paper. 6 Blow across the connector end face from a distance of 6 to 8 inches using filtered, dry, compressed air. Aim the compressed air at a shallow angle to the fiber end face.
Making Measurements Cleaning Connections for Accurate Measurements Although foam swabs can leave filmy deposits, these deposits are very thin, and the risk of other contamination buildup on the inside of adapters greatly outweighs the risk of contamination by foam swabs. 2 Clean the adapter with the foam swab. 3 Dry the inside of the adapter with a clean, dry, foam swab. 4 Blow through the adapter using filtered, dry, compressed air. Nitrogen gas or compressed dust remover can also be used.
3 Addressing and Initializing the Instrument 3- 3 To change the GPIB address 3-4 Making Measurements 3- 5 Commands are grouped in subsystems 3-7 Measurement instructions give quick results 3-9 The format of returned data 3-15 Monitoring the Instrument 3- 16 Status registers 3-17 Queues 3-22 Reviewing SCPI Syntax Rules 3- 23 Example Programs 3- 28 Example 1. Measure a DFB laser 3-30 Example 2. Measure WDM channels 3-32 Example 3. Measure WDM channel drift 3-34 Example 4.
Programming Programming Programming This chapter explains how to program the Agilent 86120C. The programming syntax conforms to the IEEE 488.2 Standard Digital Interface for Programmable Instrumentation and to the Standard Commands for Programmable Instruments (SCPI). Where to begin… The programming examples for individual commands in this manual are written in HP1 BASIC 6.0 for an HP 9000 Series 200/300 Controller. For more detailed information regarding the GPIB, the IEEE 488.
Programming Addressing and Initializing the Instrument Addressing and Initializing the Instrument The Agilent 86120C’s GPIB address is configured at the factory to a value of 20. You must set the output and input functions of your programming language to send the commands to this address. You can change the GPIB address from the front panel as described in “To change the GPIB address” on page 3- 4.
Programming Addressing and Initializing the Instrument Notice in the example above, that the commands are sent to an instrument address of 720. This indicates address 20 on an interface with select code 7. Pressing the green Preset key does not change the GPIB address. Set single acquisition mode An advantage of using the *RST command is that it sets the Agilent 86120C into the single measurement acquisition mode.
Programming Making Measurements Making Measurements Making measurements remotely involves changing the Agilent 86120C’s settings, performing a measurement, and then returning the data to the computer. The simplified block diagram of the Agilent 86120C shown here lists some of the available programming commands. Each command is placed next to the instrument section it configures or queries data from.
Programming Making Measurements After collecting the uncorrected data, the Agilent 86120C searches the data for the first 200 peak responses. (For WLIMit:OFF, searching starts at 1650 nm and progresses towards 1270 nm. For WLIMit:ON, searching starts at WLIMit:START and progresses toward WLIMit:STOP.) These peak values are then placed into the corrected data buffer. Each peak value consists of an amplitude and wavelength measurement. Amplitude and wavelength correction factors are applied to this data.
Programming Making Measurements Commands are grouped in subsystems The Agilent 86120C commands are grouped in the following subsystems. You’ll find a description of each command in Chapter 4, “Programming Commands”. Subsystem Measurement Instructions Purpose of Commands Perform frequency, wavelength, and wavenumber measurements. CALCulate1 Queries uncorrected frequency-spectrum data. CALCulate2 Queries corrected peak data and sets wavelength limits.
Programming Making Measurements Table 2-4.
Programming Making Measurements Measurement instructions give quick results The easiest way to measure wavelength, frequency, or power is to use the MEASure command. The MEASure command is one of four measurement instructions: MEASure, READ, FETCh, and CONFigure. The syntax for measurement instructions is documented in “Measurement Instructions” on page 4- 15. Each measurement instruction has an argument that controls the measurement update rate. This is equivalent to using the NORMAL and FAST softkeys.
Programming Making Measurements A common programming error is to send the :MEASure command when the instrument is in the continuous measurement acquisition mode. Because :MEASure contains an :INIT:IMM command, which expects the single measurement acquisition mode, an error is generated, and the INIT command is ignored. :READ command The READ command works like the MEASure command except that it does not configure the instrument’s settings.
Programming Making Measurements Also, because new data is not collected, FETCh is especially useful when characterizing transient data. FETCh does not reconfigure the display. For example, if the display is in the Peak WL mode, sending :FETCh:ARRay does not configure the display to the List by WL even though an array of data is returned to the computer. A common programming error occurs when the :FETCh command is used after an *RST command. This generates error number –230, “Data corrupt or stale”.
Programming Making Measurements ARRay and the SCPI standard According to the SCPI command reference, the ARRay command causes an instrument to take multiple measurements. (A parameter indicates the number of measurements to take.) However, the Agilent 86120C’s ARRay command refers to the measurements performed for one measurement sweep; this results in an array of measured signals. Because the parameter does not apply, any parameter sent will be ignored by the instrument.
Programming Making Measurements The benefit of non- sequential commands is that, in some situations, they can reduce the overall execution times of programs. For example, you can set the peak excursion, peak threshold, and elevation and use a *WAI command at the end to save time. However, non- sequential commands can also be a source of annoying errors. Always use the *OPC query or *WAI command with the non- sequential commands to ensure that your programs execute properly.
Programming Making Measurements Measure delta, drift, and signal- to- noise To select a measurement, use one of the following STATe commands: CALC3:DELT:POW:STAT (delta power) CALC3:DELT:WAV:STAT (delta wavelength) CALC3:DELT:WPOW:STAT (delta power and wavelength) CALC3:DRIF:STAT (drift) CALC3:SNR:STAT (signal-to-noise ratios) CALC3:ASNR:STAT (signal-to-noise ratio averaging) If you select a drift measurement, you can select one of the following additional states: CALC3:DRIF:DIFF:STAT (difference) CALC3:D
Programming Making Measurements The format of returned data Measurements are returned as strings All measurement values are returned from the Agilent 86120C as ASCII strings. When an array is returned, the individual values are separated by the comma character. Determine the number of data points When a FETCh, READ, or MEASure command is used (with ARRay specified), the first returned value indicates the total number of measurement values returned in the query.
Programming Monitoring the Instrument Monitoring the Instrument Almost every program that you write will need to monitor the Agilent 86120C for its operating status. This includes querying execution or command errors and determining whether or not measurements have been completed. Several status registers and queues are provided to accomplish these tasks. In this section, you’ll learn how to enable and read these registers.
Programming Monitoring the Instrument Status registers The Agilent 86120C provides four registers which you can query to monitor the instrument’s condition. These registers allow you to determine the following items: • Status of an operation • Availability of the measured data • Reliability of the measured data All four registers are shown in the figure on the following page and have the following uses: Register Definition Status Byte Monitors the status of the other three registers.
Programming Monitoring the Instrument 3-18
Programming Monitoring the Instrument The Status Byte Register can be read using either the *STB? common command or the GPIB serial poll command. Both commands return the decimal- weighted sum of all set bits in the register. The difference between the two methods is that the serial poll command reads bit 6 as the Request Service (RQS) bit and clears the bit which clears the SRQ interrupt.
Programming Monitoring the Instrument Table 3-7. Bits in Questionable Status Register Bit Definition 0, 1, and 2 not used 3 POWer - indicating that the instrument is measuring too high of a power. 3 through 8 not used 9 Maximum signals - indicating that the instrument has found the maximum number of signals. 10 Drift Reference - indicating that the number of reference signals is different from the current number of input signals.
Programming Monitoring the Instrument Enabling register bits with masks Several masks are available which you can use to enable or disable individual bits in each register. For example, you can disable the Hardcopy bit in the OPERation Status Register so that even though it goes high, it can never set the summary bit in the status byte high. Use the *SRE common command to set or query the mask for the Status Byte Register.
Programming Monitoring the Instrument Queues There are two queues in the instrument: the output queue and the error queue. The values in the output queue and the error queue can be queried. Output queue The output queue stores the instrument responses that are generated by certain commands and queries that you send to the instrument. The output queue generates the Message Available summary bit when the output queue contains one or more bytes.
Programming Reviewing SCPI Syntax Rules Reviewing SCPI Syntax Rules SCPI command are grouped in subsystems In accordance with IEEE 488.2, the instrument’s commands are grouped into “subsystems.” Commands in each subsystem perform similar tasks.
Programming Reviewing SCPI Syntax Rules OUTPUT 720;”:MEAS:SCAL:POW? MAX” Programs written in long form are easily read and are almost self- documenting. Using short form commands conserves the amount of controller memory needed for program storage and reduces the amount of I/O activity.
Programming Reviewing SCPI Syntax Rules Combine commands from different subsystems You can send commands and program queries from different subsystems on the same line. Simply precede the new subsystem by a semicolon followed by a colon. In the following example, the colon and semicolon pair before DISP allows you to send a command from another subsystem.
Programming Reviewing SCPI Syntax Rules is taken care of automatically when you include the entire instruction in a string. Several representations of a number are possible. For example, the following numbers are all equal: 28 0.28E2 280E-1 28000m 0.028K 28E-3K If a measurement cannot be made, no response is given and an error is placed into the error queue. For example, *RST FETCh:POW? will timeout the controller and place a Data stale or corrupt error in the error queue. Table 3-9.
Programming Reviewing SCPI Syntax Rules Program message terminator The string of instructions sent to the instrument are executed after the instruction terminator is received. The terminator may be either a new- line (NL) character, the End- Or- Identify (EOI) line asserted, or a combination of the two. All three ways are equivalent. Asserting the EOI sets the EOI control line low on the last byte of the data message. The NL character is an ASCII linefeed (decimal 10).
Programming Example Programs Example Programs The following example programs are provided in this section: Example Example Example Example Example Example 1. 2. 3. 4. 5. 6.
Programming Example Programs The Err_mngmt subroutine is used to actually read the value of the event status register. Examples 1 through 5 call this subroutine. FNIdentity function When this function is called, it resets the instrument and queries the instrument’s identification string which is displayed on the computer’s screen by the calling function. To accomplish this task, the FNIdentity function uses the *RST, *OPC?, and *IDN? common commands. This function is called from Examples 1 through 5.
Programming Example Programs Example 1. Measure a DFB laser This program measures the power and wavelength of a DFB laser. It first sets the Agilent 86120C in the single- acquisition measurement mode. Then, it triggers the Agilent 86120C with the MEASure command to capture measurement data of the input spectrum. Because the data is stored in the instrument’s memory, it can be queried as needed. Refer to the introduction to this section for a description of each subroutine that is contained in this program.
Programming Example Programs Identity:DEF FNIdentity$; COM /Instrument/ @MwmV DIM Identity$[50] Identity$="" OUTPUT @Mwm;"*RST" OUTPUT @Mwm;"*OPC?" ENTER @Mwm;Opc_done OUTPUT @Mwm;"*IDN?" ENTER @Mwm;Identity$ RETURN Identity$ FNEND 3-31
Programming Example Programs Example 2. Measure WDM channels This program measures the multiple laser lines of a WDM system. It measures both the power and wavelengths of each line. First, the program sets the Agilent 86120C in the single- acquisition measurement mode. Then, it triggers the Agilent 86120C with the MEASure command to capture measurement data of the input spectrum. Because the data is stored in the instrument’s memory, it can be queried as needed.
Programming Example Programs PRINT Err_msg$ UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND Err$,"+0") Subend:SUBEND Set_ese:SUB Set_ese COM /Instrument/ @Mwm OUTPUT @Mwm; "*ESE";IVAL("00110100",2) SUBEND Identity:DEF FNIdentity$; COM /Instrument/ @Mwm DIM Identity$[50] Identity$="" OUTPUT @Mwm;"*RST" OUTPUT @Mwm;"*OPC?" ENTER @Mwm;Opc_done OUTPUT @Mwm;"*IDN?" ENTER @Mwm;Identity$ RETURN Identity$ FNEND 3-33
Programming Example Programs Example 3. Measure WDM channel drift This program measures the drift of channels in a WDM system. It measures drift in both power and wavelength of each line. First, the program sets the Agilent 86120C in the continuous- acquisition measurement mode. Then, it measures drift using commands from the CALCulate3 subsystem. Notice the use of the Tempo subroutine to pause the program for 10 seconds while the Agilent 86120C measures the drift on the system.
Programming Example Programs ! Query reference wavelengths and powers OUTPUT @Mwm;":CALC3:DATA? WAV" ENTER @Mwm USING "#,K";Current_ref_wl(*) OUTPUT @Mwm;":CALC3:DATA? POW" ENTER @Mwm USING "#,K";Current_ref_pwr(*) ! Turn off drift reference state Cmd_opc(":CALC3:DRIF:REF:STAT OFF") Err_mngmt(":CALC3:DRIF:REF:STAT OFF") ! Turn on drift max min calculation Cmd_opc(":CALC3:DRIF:DIFF:STAT ON") Err_mngmt(":CALC3:DRIF:DIFF:STAT ON") Tempo(10) ALLOCATE Current_diff_wl(1:Nb_pt) ALLOCATE Current_diff_pw(1:Nb_pt) !
Programming Example Programs Subend:SUBEND Set_ese:SUB Set_ese COM /Instrument/ @Mwm OUTPUT @Mwm;"*ESE ";IVAL("00110100",2) SUBEND Identity:DEF FNIdentity$; COM /Instrument/ @Mwm DIM Identity$[50] Identity$="" OUTPUT @Mwm;"*RST" OUTPUT @Mwm;"*OPC?" ENTER @Mwm;Opc_done OUTPUT @Mwm;"*IDN?" ENTER @Mwm;Identity$ RETURN Identity$ FNEND Cmd_opc:SUB Cmd_opc(Set_cmd$) COM /Instrument/ @Mwm OUTPUT @Mwm;Set_cmd$ OUTPUT @Mwm;"*OPC?" ENTER @Mwm;Opc_done$ SUBEND Tempo:SUB Tempo(Temp) FOR I=Temp TO 0 STEP -1) DISP "Wait
Programming Example Programs Example 4. Measure WDM channel separation This program measures the line separations on a WDM system. It measures separation (delta) between power and wavelength of each line using commands from the CALCulate3 subsystem. Refer to the introduction to this section for a description of each subroutine that is contained in this program.
Programming Example Programs ";(Delta_wl(I)+((NOT I=1)*Delta_wl(1)))/1.0E-9;" nm. Absolute line level is : ";Delta_pwr(I)+(NOT I=1)*Delta_pwr(1);" dBm" PRINT USING "17A,2D,6A,M4D.3D,23A,2D,6A,S2D.2D,3A";"Delta Wl to line ",I+1," is : ";(Delta_wl(I+1)-(NOT I=1)*Delta_wl(I))/1.E-9;" nm, Delta Pwr to line ",I+1," is : ";(I=1)*(Delta_pwr(I+1))+(NOT I=1)*(Delta_pwr(I+1)-Delta_pwr(I));" dB" NEXT I PRINT USING "6A,2D,17A,M4D.3D,31A,S2D.2D,4A";"Line : ";I;" wavelength is : ";(Delta_wl(1)+Delta_wl(Nb_pt))/1.
Programming Example Programs Example 5. Measure signal- to- noise ratio of each WDM channel This program measures signal- to- noise ratios on a WDM system. It measures the ratio for each line using commands from the CALCulate3 subsystem. Refer to the introduction to this section for a description of each subroutine that is contained in this program.
Programming Example Programs FOR I=1 TO Nb_pt PRINT USING "7A,2D,17A,M4D.3D,25A,S2D.2D,22A,2D.2D,3A";"Line : ";I;" wavelength is : ";Current_wl(I)/1.
Programming Example Programs Example 6. Increase a source’s wavelength accuracy This example program uses the Agilent 86120C to increase the absolute wavelength accuracy of Agilent 8167A, 8168B, and 8168C Tunable Laser Sources. Essentially, the Agilent 86120C’s accuracy is transferred to the tunable laser source. The absolute accuracy of the tunable laser source is increased from <±0.1 nm to <±0.003 nm which is the Agilent 86120C’s absolute accuracy (at 1550 nm).
Programming Example Programs COM Current_wl,Diff_wl.
Programming Lists of Commands Lists of Commands Table 3-10. Programming Commands (1 of 5) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. Common Commands *CLS *ESE *ESR? *IDN? *OPC *RCL *RST *SAV *SRE *STB *TRG *TST? *WAI Clears all event registers and the error queue. Sets the bits in the standard-event status enable register. Queries value standard-event status register. Queries instrument model number and firmware version.
Programming Lists of Commands Table 3-10. Programming Commands (2 of 5) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. CALCulate1 (CALC1) Subsystem :CALCulate1:DATA? Queries the uncorrected frequency-spectrum data of the input signal. S :CALCulate1:TRANsform:FREQuency:POINts? Sets and queries the number of points in the data set. S Queries the corrected frequency-spectrum data of the input signal. Sets the peak excursion limit.
Programming Lists of Commands Table 3-10. Programming Commands (3 of 5) Command Description Codes: S indicates a standard SCPI command. I indicates an instrument specific command. :CALCulate3:DELTa:REFerence[:WAVelength] Selects the signal to be used as the reference for the DELTa calculations. :CALCulate3:DELTa:REFerence:WNUMber Selects the signal to be used as the reference for the DELTa calculations. :CALCulate3:DELTa:WAVelength[:STATe] Turns the delta wavelength measurement mode on and off.
Programming Lists of Commands Table 3-10. Programming Commands (4 of 5) Command Description Codes: S indicates a standard SCPI command. I indicates an instrument specific command. :CALCulate3:FPERot:POWer:[WAVelength]? Queries the power wavelength of the selected modes. :CALCulate3:FPERot:POWer:FREQuency? Queries the power frequency of the selected modes. :CALCulate3:FPERot:POWer:WNUMber? Queries the power wavenumber of the selected modes.
Programming Lists of Commands Table 3-10. Programming Commands (5 of 5) Command Description Codes: S indicates a standard SCPI command. I indicates an instrument specific command. :SENSe:CORRection:ELEVation Sets the elevation value used by the instrument to compensate for air dispersion. :SENSe:CORRection:OFFSet:MAGNitude Sets the power offset value used by the instrument. :SENSe:CORRection:MEDium Sets the instrument to return the wavelength reading in a vacuum when the parameter is on.
Programming Lists of Commands Table 3-11.
Programming Lists of Commands Table 3-11.
Programming Lists of Commands 3-50
4 Common Commands 4- 3 Measurement Instructions 4- 15 CALCulate1 Subsystem 4- 25 CALCulate2 Subsystem 4- 31 CALCulate3 Subsystem 4- 44 CONFigure Measurement Instruction 4- 74 DISPlay Subsystem 4- 75 FETCh Measurement Instruction 4- 79 HCOPy Subsystem 4- 80 MEASure Measurement Instruction 4- 81 READ Measurement Instruction 4- 82 SENSe Subsystem 4- 83 STATus Subsystem 4- 90 SYSTem Subsystem 4- 97 TRIGger Subsystem 4- 103 UNIT Subsystem 4- 107 Programming Commands
Programming Commands Programming Commands Programming Commands This chapter is the reference for all Agilent 86120C programming commands. Commands are organized by subsystem. Table 4-12. Notation Conventions and Definitions Convention Description < > Angle brackets indicate values entered by the programmer. | ”Or” indicates a choice of one element from a list. [] Square brackets indicate that the enclosed items are optional.
Programming Commands Common Commands Common Commands Common commands are defined by the IEEE 488.2 standard. They control generic device functions which could be common among many different types of instruments. Common commands can be received and processed by the instrument whether they are sent over the GPIB as separate program messages or within other program messages. *CLS The *CLS (clear status) command clears all the event status registers summarized in the status byte register.
Programming Commands Common Commands is a mask from 0 to 255. Description The event status enable register contains a mask value for the bits to be enabled in the event status register. A bit set to one (1) in the event status enable register enables the corresponding bit in the event status register to set the event summary bit in the status byte register. A zero (0) disables the bit.
Programming Commands Common Commands *ESR? The *ESR (event status register) query returns the value of the event status register. Syntax *ESR? Description When you read the standard event status register, the value returned is the total of the bit weights of all of the bits that are set to one at the time you read the byte. The following table shows each bit in the event status register and its bit weight. The register is cleared when it is read. Table 4-14.
Programming Commands Common Commands *IDN? The *IDN? (identification number) query returns a string value which identifies the instrument type and firmware version. Syntax *IDN? Description An *IDN? query must be the last query in a program message. Any queries after the *IDN? query in a program message are ignored. The maximum length of the identification string is 50 bytes. Query Response The following identification string is returned. The third entry is the instrument’s serial number.
Programming Commands Common Commands *OPC The *OPC (operation complete) command sets the operation complete bit in the event status register when all pending device operations have finished. Syntax *OPC *OPC? Description The *OPC? query places an ASCII “1” in the output queue when all pending device operations have finished. This command is useful when the computer is sending commands to other instruments.
Programming Commands Common Commands *RST The *RST (reset) command returns the Agilent 86120C to a known condition. Syntax *RST Description For a listing of reset conditions, refer to the following table. This command cannot be issued as a query. Since this command places the instrument in single measurement acquisition mode, any current data is marked as invalid and a measurement query such as :FETCh? results in error number –230, “Data corrupt or stale”.
Programming Commands Common Commands Table 4-15.
Programming Commands Common Commands offset, signal- to- noise auto mode on/off, wavelength limit on/off, wavelength limit start, wavelength limit stop, and signal- to- noise average count. *SRE The *SRE (service request enable) command sets the bits in the service request enable register. Syntax *SRE *SRE? is defined as an integer mask from 0 to 255. Description The service request enable register contains a mask value for the bits to be enabled in the status byte register.
Programming Commands Common Commands Query Response from 0 to 63 or from 128 to 191. Example OUTPUT 720;”*SRE 32” In this example, the command enables ESB (event summary) bit 5 in the status byte register to generate a service request.
Programming Commands Common Commands *STB? The *STB (status byte) query returns the current value of the instrument’s status byte. Syntax *STB? Description The master summary status (MSS) bit 6 indicates whether or not the device has at least one reason for requesting service. When you read the status byte register, the value returned is the total of the bit weights of all of the bits set to one at the time you read the byte.
Programming Commands Common Commands *TRG The *TRG (trigger) command is identical to the group execute trigger (GET) message or RUN command. Syntax *TRG Description This command acquires data according to the current settings. This command cannot be issued as a query. If a measurement is already in progress, a trigger is ignored, and an error is generated. Example The following example starts the data acquisition according to the current settings.
Programming Commands Common Commands *WAI The *WAI command prevents the instrument from executing any further commands until the current command has finished executing. Syntax *WAI Description All pending operations are completed during the wait period. This command cannot be issued as a query.
Programming Commands Measurement Instructions Measurement Instructions Use the measurement instructions documented in this section to perform measurements and return the desired results to the computer. Four basic measurement instructions are used: CONFigure, FETCh, READ, and MEASure. Because the command trees for each of these four basic measurement instructions are identical, only the MEASure tree is documented. To perform a measurement, append to the measurement instruction a POWer or LENGth function.
Programming Commands Measurement Instructions The commands in this subsystem have the following command hierarchy: {:MEASure | :READ[?] | :FETCh[?] | :CONFigure[?]} {:ARRay | [:SCALar] } :POWer[?] :FREQuency[?] :WAVelength[?] :WNUMber[?] 4-16
Programming Commands Measurement Instructions MEASure{:ARRay | [:SCALar]} :POWer? Returns amplitude values. Syntax Description :POWer? [[,]] Used With SCALar optional ignored ARRay ignored ignored When used with a :SCALar command, a single value is returned. The display is placed in the single- wavelength mode, and the marker is placed on the signal having a power level that is closest to the parameter.
Programming Commands Measurement Instructions Examples :CONF:ARR:POW :FETC:ARR:POW? :READ:ARR:POW? :MEAS:ARR:POW? :CONF:SCAL:POW -10 dBm :FETC:SCAL:POW? MAX :READ:SCAL:POW? MIN :MEAS:SCAL:POW? DEF Query Response The following line is an example of a returned string when :MEAS:SCAL:POW? MAX is sent: -5.88346500E+000 If six laser lines are located and :MEAS:ARR:POW? is sent, the following string could be returned.
Programming Commands Measurement Instructions MEASure{:ARRay | [:SCALar]} :POWer:FREQuency? Returns frequency values. Syntax :POWer:FREQuency? [[,]] Used With SCALar optional optional ARRay ignoreda optional a. Although ignored, this argument must be present if the resolution argument is specified. Description When used with a :SCALar command, a single value is returned.
Programming Commands Measurement Instructions Constants Examples DEFault The current marker position MAXimum 0.01 resolution (fast update) MINimum 0.001 resolution (normal) DEFault Current resolution :CONF:ARR:POW:FREQ DEF, MIN :FETC:ARR:POW:FREQ? DEF, MAX :READ:ARR:POW:FREQ? :MEAS:ARR:POW:FREQ? :CONF:SCAL:POW:FREQ 230.8THZ, MAX :FETC:SCAL:POW:FREQ? 230.8THZ, MIN :READ:SCAL:POW:FREQ? 230.8THZ :MEAS:SCAL:POW:FREQ? 230.
Programming Commands Measurement Instructions MEASure{:ARRay | [:SCALar]} :POWer:WAVelength? Returns wavelength values. Syntax :POWer:WAVelength? [[,]] Used With SCALar optional optional ARRay ignoreda optional a. Although ignored, this argument must be present if the resolution argument is specified. Description When used with a :SCALar command, a single value is returned.
Programming Commands Measurement Instructions Constants Examples MAXimum 0.01 resolution (fast update) MINimum 0.001 resolution (normal) DEFault Current resolution :CONF:ARR:POW:WAV DEF, MAX :FETC:ARR:POW:WAV? DEF, MIN :READ:ARR:POW:WAV? :MEAS:ARR:POW:WAV? :CONF:SCAL:POW:WAV 1300NM, MAX :FETC:SCAL:POW:WAV? 1300NM, MIN :READ:SCAL:POW:WAV? 1300NM :MEAS:SCAL:POW:WAV? 1300NM Query Response The following line is an example of a returned string when :MEAS:SCAL:POW:WAV? MAX is sent: +1.
Programming Commands Measurement Instructions MEASure{:ARRay | [:SCALar]} :POWer:WNUMber? Returns a wave number value. Syntax :POWer:WNUMber? [[,]] Used With SCALar optional optional ARRay ignoreda optional a. Although ignored, this argument must be present if the resolution argument is specified. Description When used with a :SCALar command, a single value is returned.
Programming Commands Measurement Instructions Constants MAXimum 0.01 resolution (fast update) MINimum 0.
Programming Commands CALCulate1 Subsystem CALCulate1 Subsystem Use the CALCulate1 commands to query uncorrected frequency- spectrum data. In NORMAL measurement update mode, 15,047 values are returned. If the Agilent 86120C is set for FAST measurement update mode (low resolution), 7,525 values are returned.
Programming Commands CALCulate1 Subsystem DATA? Queries uncorrected frequency- spectrum data of the input laser line. Syntax :CALCulate1:DATA? Attribute Summary Preset State: not affected SCPI Compliance: standard Query Only Description The returned values are proportional to squared Watts (linear) units. No amplitude or frequency correction is applied to the values.
Programming Commands CALCulate1 Subsystem When NORMAL measurement mode is selected, the uncorrected frequency domain data consists of 64K values. Only the frequency domain data corresponding to 1270–1650 wavelength (in vacuum) is returned (15,047 values). In FAST measurement mode, the data consists of 32K values of which 7,525 values are returned. In NORMAL measurement mode, the frequency spacing between values is uniform and is equal to 3.613378 GHz.
Programming Commands CALCulate1 Subsystem This query will generate a “Settings conflict” error if the instrument is in the signal- to- noise average application.
Programming Commands CALCulate1 Subsystem TRANsform:FREQuency:POINts Sets the size of the fast Fourier transform (FFT) performed by the instrument. Syntax :CALCulate1:TRANsform:FREQuency:POINts{?| { | MINimum | MAXimum}} Sets FFT size. Must be either 15,047 or 7,525. Other values result in an error.
Programming Commands CALCulate1 Subsystem Query Response For normal update: +15,047 For fast update: +7,525 4-30
Programming Commands CALCulate2 Subsystem CALCulate2 Subsystem Use the CALCulate2 commands to query corrected values frequencyspectrum data.
Programming Commands CALCulate2 Subsystem DATA? Queries the corrected peak data of the input laser line. Syntax :CALCulate2:DATA? {FREQuency | POWer | WAVelength | WNUMber} Constant Description FREQuency Queries the array of laser-line frequencies after the peak search is completed. If :CALC2:PWAV:STAT is on, the power-weighted average frequency is returned. POWer Queries the array of laser-line powers after the peak search is completed. If :CALC2:PWAV:STAT is on, the total input power is returned.
Programming Commands CALCulate2 Subsystem When there is no input signal, the POWer query returns –200 dBm; the WAVelength query returns 100 nm (1.0E–7). PEXCursion Sets the peak excursion limit used by the Agilent 86120C to determine valid laser line peaks. Syntax :CALCulate2:PEXCursion{?| { | MINimum | MAXimum | DEFault}} represents logarithmic units in dB. Valid range is 1 to 30 dB.
Programming Commands CALCulate2 Subsystem Non-sequential command Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument. Refer to “Always force the Agilent 86120C to wait for non-sequential commands” on page 3-12 for more information. POINts? Queries the number of points in the data set.
Programming Commands CALCulate2 Subsystem DEFault 10 dB Attribute Summary Non- sequential command Preset State: 10 dB *RST State: 10 dB SCPI Compliance: instrument specific Description A laser line is identified as a valid peak if its amplitude is above the maximum amplitude minus the peak threshold value. The subtraction is done in dB units. This setting works in conjunction with the peak excursion setting to determine which responses are located. Refer to “PEXCursion” on page 4- 33.
Programming Commands CALCulate2 Subsystem Turning power- weighted average mode on while making delta, FabryPerot, or signal- to- noise measurements results in a “–221 Settings conflict” error.
Programming Commands CALCulate2 Subsystem WLIMit[:STATe] Turns wavelength limiting on and off. Syntax :CALCulate2:WLIMit[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Non- sequential command Preset State: on *RST State: on SCPI Compliance: instrument specific Description When this function is on, the Agilent 86120C has an input range from the WLIMit STARt to the WLIMit STOP. When this function is off, the instrument displays peaks over the full wavelength range.
Programming Commands CALCulate2 Subsystem WLIMit:STARt:FREQuency Sets the start frequency for the wavelength limit range. Syntax :CALCulate2:WLIMit:STARt:FREQuency {?|{ | MINimum | MAXimum }} is a frequency value that is within the following limits: Constant Description MINimum 181.6924 THz (1650 nm) MAXimum wavelength limit stop value Attribute Summary Non- sequential command Preset State: 181.6924 THz *RST State: 181.
Programming Commands CALCulate2 Subsystem WLIMit:STARt[:WAVelength] Syntax CALCulate2:WLIMit:STARt[:WAVelength] {?|{ | MINimum | MAXimum}} is a wavenumber value that is within the following limits: Constant Description MINimum 1270 nm MAXimum wavelength limit stop value Attribute Summary Non- sequential command Preset State: 1270 nm *RST State: 1270 nm SCPI Compliance: instrument specific Description This command sets the starting range for the wavelength limit.
Programming Commands CALCulate2 Subsystem WLIMit:STARt:WNUMber Sets the starting wavenumber for the wavelength limit range. Syntax :CALCulate2:WLIMit:STARt:WNUMber {?|{ | MINimum | MAXimum}} is a wavenumber value that is within the following limits: Constant Description MINimum 6060 cm-1 (1650 nm) MAXimum wavelength limit stop value Attribute Summary Non- sequential command Preset State: 6.060606E5 m- 1 *RST State: 6.
Programming Commands CALCulate2 Subsystem WLIMit:STOP:FREQuency Sets the stopping frequency for the wavelength limit range. Syntax :CALCulate2:WLIMit:STOP:FREQuency {?|{ | MINimum | MAXimum }} is a frequency value that is within the following limits: Constant Description MINimum start wavelength limit MAXimum 236.0571 THz (1270 nm) Attribute Summary Non- sequential command Preset State: 236.0571 THz *RST State: 236.
Programming Commands CALCulate2 Subsystem WLIMit:STOP[:WAVelength] Sets the stopping wavelength for the wavelength limit range. Syntax :CALCulate2:WLIMit:STOP[:WAVelength] {?|{ | MINimum | MAXimum }} is a wavelength value that is within the following limits: Constant Description MINimum start wavelength limit MAXimum 1650.
Programming Commands CALCulate2 Subsystem WLIMit:STOP:WNUMber Sets the stopping wavenumber for the wavelength limit range. Syntax :CALCulate2:WLIMit:STOP:WNUMber {?|{ | MINimum | MAXimum }} is a wavenumber value that is within the following limits: Constant Description MINimum start wavelength limit MAXimum 7874 cm-1 (1270 nm) Attribute Summary Non- sequential command Preset State: 7.87401E5 m- 1 *RST State: 7.
Programming Commands CALCulate3 Subsystem CALCulate3 Subsystem Use the CALCulate3 commands to perform delta, drift, signal- to- noise, and Fabry- Perot measurements.
Programming Commands CALCulate3 Subsystem :FPERot [:STATE] :FWHM [:WAVelength]? :FREQuency? :WNUMber? :MEAN [:WAVelength]? :FREQuency? :WNUMber? :MODE [:WAVelength]? :FREQuency? :WNUMber? :PEAK [:WAVelength]? :FREQuency? :WNUMber? :POWer? :POWer [:WAVelength]? :FREQuency? :WNUMber? :SIGMa [:WAVelength]? :FREQuency? :WNUMber? :POINts? :PRESet :SNR :AUTO :REFerence :FREQuency [:WAVelength] :WNUMber [:STATe] 4-45
Programming Commands CALCulate3 Subsystem ASNR:CLEar Clears the number of measurements used in the average signal- tonoise calculation. Syntax :CALCulate3:ASNR:CLEar Attribute Summary Preset State: not affected *RST State: not affected SCPI Compliance: instrument specific Description This command clears the number of measurements used in the average signal- to- noise calculation. The current measurement is used as the new reference for the average signal- to- noise calculation.
Programming Commands CALCulate3 Subsystem ASNR:COUNt Sets the number of measurements to be used for the average signal- tonoise calculation.
Programming Commands CALCulate3 Subsystem ASNR[:STATe] Turns the average signal- to- noise ratio on or off. Syntax :CALCulate3:ASNR[:STATe] {?|{ ON | OFF | 1 | 0 }} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description This command turns the average signal- to- noise calculation on or off. Only one of the CALCulate3 calculations (ASNR, DELTa, DRIFt, or SNR) can be turned on at a time.
Programming Commands CALCulate3 Subsystem DATA? Queries the data resulting from delta, drift, and signal- to- noise measurements. Syntax :CALCulate3:DATA? {POWer | FREQuency | WAVelength | WNUMber} Argument Description POWer Queries the array of laser-line powers after the calculation is completed. FREQuency Queries the array of laser-line frequencies after the calculation is completed. WAVelength Queries the array of laser-line wavelengths after the calculation is completed.
Programming Commands CALCulate3 Subsystem DELTa:POWer[:STATe] Turns the delta- power measurement mode on and off. Syntax :CALCulate3:DELTa:POWer[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description When this state is on, the power of the reference laser line is subtracted from the power values of all laser lines except the reference.
Programming Commands CALCulate3 Subsystem DELTa:REFerence:FREQuency Selects the reference laser line for DELTa calculations. Syntax :CALCulate3:DELTa:REFerence:FREQuency{?| { | MINimum | MAXimum}} is a frequency value that is within the following limits: Constant Description MINimum 181.6924 THz MAXimum 236.0571 THz Attribute Summary Preset State: 236.0571 THz (1270 nm) *RST State: 236.
Programming Commands CALCulate3 Subsystem DELTa:REFerence[:WAVelength] Selects the reference laser line for DELTa calculations. Syntax :CALCulate3:DELTa:REFerence[:WAVelength]{?| { | MINimum | MAXimum}} is a wavelength value that is within the following limits: Constant Description MINimum 1270 nm MAXimum 1650 nm Attribute Summary Preset State: 1270 nm (236.0571 THz) *RST State: 1270 nm (236.
Programming Commands CALCulate3 Subsystem DELTa:REFerence:WNUMber Selects the reference laser line for delta calculations.
Programming Commands CALCulate3 Subsystem DELTa:WAVelength[:STATe] Turns the delta wavelength measurement mode on and off. Syntax :CALCulate3:DELTa:WAVelength[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description When on, the wavelength of the reference laser line is subtracted from the wavelength values of all laser lines except the reference.
Programming Commands CALCulate3 Subsystem DELTa:WPOWer[:STATe] Turns the delta wavelength and power measurement mode on and off. Syntax :CALCulate3:DELTa:WPOWer[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description When on, the wavelength of the reference laser line is subtracted from the wavelength values of all laser lines except the reference.
Programming Commands CALCulate3 Subsystem DRIFt:DIFFerence[:STATe] Sets the drift calculation to subtract the minimum values measured from the maximum values measured. Syntax :CALCulate3:DRIFt:DIFFerence[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description Use the CALC3:DRIF:PRES command to turn off all the drift states before turning on this state.
Programming Commands CALCulate3 Subsystem DRIFt:MAXimum[:STATe] Sets the drift calculation to return the maximum power and frequency values measured. Syntax :CALCulate3:DRIFt:MAXimum[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description Use the CALC3:DRIF:PRES command to turn off all the drift states before turning on this state. The CALC3:DATA? query returns the maximum power and frequency.
Programming Commands CALCulate3 Subsystem DRIFt:MINimum[:STATe] Sets the drift calculation to return the minimum power and frequency values measured. Syntax :CALCulate3:DRIFt:MINimum[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description Use the CALC3:DRIF:PRES command to turn off all the drift states before turning on this state. The CALC3:DATA? query returns the minimum power or frequency.
Programming Commands CALCulate3 Subsystem DRIFt:PRESet Turns off all the drift states for DIFFerence, MAXimum, MINimum, and REFerence. Syntax :CALCulate3:DRIFt:PRESet Attribute Summary Preset State: unaffected by *RST State: unaffected by SCPI Compliance: instrument specific Command Only Description This command allows the CALC3:DATA? query to return the difference between the current measurement and the reference. DRIFt:REFerence:RESet Places the current list of laser lines into the reference list.
Programming Commands CALCulate3 Subsystem DRIFt:REFerence[:STATe] Turns on and off the drift reference state. Syntax :CALCulate3:DRIFt:REFerence[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description When this command is set to on, the CALC3:DATA? command returns the reference laser lines. Use the CALC3:DRIF:PRES command to turn off all the drift states before turning on the drift reference state.
Programming Commands CALCulate3 Subsystem DRIFt[:STATe] Turns on and off the drift measurement calculation. Syntax :CALCulate3:DRIFt[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description When the drift mode is first turned on, the current list of laser lines is placed into the reference. All subsequent measurements take the new data, subtract the reference data, and display the differences in wavelengths and powers.
Programming Commands CALCulate3 Subsystem FPERot[:STATE] Turns on and off the Fabry- Perot measurement mode. Syntax :CALCulate3:FPERot[:STATE] {? | {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Description When the state is ON, the Agilent 86120C measures characteristics of the Fabry- Perot laser modes. The modes are defined by the peak excursion and peak threshold commands.
Programming Commands CALCulate3 Subsystem Attribute Summary Preset State: not affected *RST State: not affected SCPI Compliance: instrument specific Query only FPERot:MEAN? Queries the mean data of the selected modes. Syntax Example Query Response Attribute Summary :CALCulate3:FPERot:MEAN{[:WAVelength] | :FREQuency | :WNUMber}? Argument Description WAVelength Returns the mean wavelength of the selected modes. FREQuency Returns the mean frequency of the selected modes.
Programming Commands CALCulate3 Subsystem FPERot:MODE:SPACing? Queries the mode spacing data of the selected modes. Syntax Example Query Response Attribute Summary :CALCulate3:FPERot:MODE:SPACing{[:WAVelength] | :FREQuency | :WNUMber}? Argument Description WAVelength Returns the mode spacing wavelength of the selected modes. FREQuency Returns the mode spacing frequency of the selected modes. WNUMber Returns the mode spacing wavenumber of the selected modes. WAVelength +3.
Programming Commands CALCulate3 Subsystem FPERot:PEAK? Queries the peak data of the selected modes. Syntax Example Query Response :CALCulate3:FPERot:PEAK{[:WAVelength] | :FREQuency | :WNUMber | :POWer{[:DBM]|:WATTs}}? Argument Description WAVelength Returns the peak wavelength of the selected modes. FREQuency Returns the peak frequency of the selected modes. WNUMber Returns the peak wavenumber of the selected modes. POWer Returns the peak amplitude of the selected modes in dBm or watts.
Programming Commands CALCulate3 Subsystem FPERot:POWer? Queries the total power data of the selected modes. Syntax :CALCulate3:FPERot:POWer{[:DBM]|:WATTs}}? Argument Description DBM Returns the total power in dBm. WATTs Returns the total power in watts. Example Query Response dBm (DBM) –4.46895600E+000 watts (WATTs) +3.
Programming Commands CALCulate3 Subsystem FPERot:SIGMa? Queries the sigma data of the selected modes. Syntax Example Query Response Attribute Summary :CALCulate3:FPERot:SIGMa{[:WAVelength] | :FREQuency | :WNUMber}? Argument Description WAVelength Returns the sigma wavelength of the selected modes. FREQuency Returns the sigma frequency of the selected modes. WNUMber Returns the sigma wavenumber of the selected modes. WAVelength +2.32784700E–009 FREQuency +2.94452900E+011 WNUMber +9.
Programming Commands CALCulate3 Subsystem POINts? Queries the number of points in the data set. Syntax :CALCulate3:POINts? Attribute Summary Preset State: unaffected by RST State: unaffected by SCPI Compliance: instrument specific Query Only Description The value returned is the number of points returned by the CALC3:DATA? query. PRESet Turns off any CALCulate3 calculation that is on.
Programming Commands CALCulate3 Subsystem SNR:AUTO Selects the reference frequency value for measuring noise in the signal- to- noise calculation. Syntax :CALCulate3:SNR:AUTO{?| {ON | OFF | 1 | 0}} Constant Description ON Selects internally generated reference frequency. OFF Selects user-entered reference frequency.
Programming Commands CALCulate3 Subsystem SNR:REFerence:FREQuency Enters a frequency that can be used for the noise measurement reference in signal- to- noise calculations. Syntax :CALCulate3:SNR:REFerence:FREQuency{?| { | MINimum | MAXimum}} is a frequency value that is within the following limits: Constant Description MINimum 181.6924 THz MAXimum 236.0571 THz Attribute Summary Preset State: unaffected by *RST State: 193.4145 THz (1550.
Programming Commands CALCulate3 Subsystem SNR:REFerence[:WAVelength] Sets the wavelength used for the noise measurement reference in the signal- to- noise calculation. Syntax :CALCulate3:SNR:REFerence[:WAVelength]{?| { | MINimum | MAXimum}} is a wavelength value that is within the following limits: Constant Description MINimum 1270 nm MAXimum 1650 nm Attribute Summary Preset State: unaffected by *RST State: 1550.
Programming Commands CALCulate3 Subsystem SNR:REFerence:WNUMber Sets the wave number used for the noise measurement reference in the signal- to- noise calculation. Syntax :CALCulate3:SNR:REFerence:WNUMber{?| { | MINimum | MAXimum}} is a wave number value that is within the following limits: Constant Description MINimum 6060 cm-1 (1650 nm) MAXimum 7874 cm-1 (1270 nm) Attribute Summary Preset State: unaffected by *RST State: 6451.
Programming Commands CALCulate3 Subsystem SNR[:STATe] Turns the signal- to- noise calculation on and off. Syntax :CALCulate3:SNR[:STATe]{?| {ON | OFF | 1 | 0}} Attribute Summary Preset State: off *RST State: off SCPI Compliance: instrument specific Note Only one STATe command can be turned on at any one time. Attempting to turn more than one state on at a time results in a “–221 Settings Conflict” error.
Programming Commands CONFigure Measurement Instruction CONFigure Measurement Instruction For information on the CONFigure measurement instruction, refer to “Measurement Instructions” on page 4- 15.
Programming Commands DISPlay Subsystem DISPlay Subsystem The commands in this subsystem have the following command hierarchy: :DISPlay :MARKer: :MAXimum :LEFT :NEXT :PREVious :RIGHt [:WINDow] :GRAPhics :STATe 4-75
Programming Commands DISPlay Subsystem MARKer:MAXimum Sets the marker to the laser line that has the maximum power. Syntax :DISPlay:MARKer:MAXimum Attribute Summary Preset State: marker set to maximum- power laser line *RST State: marker set to maximum- power laser line SCPI Compliance: instrument specific Command Only MARKer:MAXimum:LEFT Moves the marker left to the next laser line.
Programming Commands DISPlay Subsystem MARKer:MAXimum:NEXT Moves the marker to the laser line with the next lower power level. Syntax :DISPlay:MARKer:MAXimum:NEXT Attribute Summary Preset State: marker set to maximum- power laser line *RST State: marker set to maximum- power laser line SCPI Compliance: instrument specific Command Only Description If the display is in the List by WL mode, it will be changed to List by Ampl before the marker is moved.
Programming Commands DISPlay Subsystem MARKer:MAXimum:RIGHt Moves the marker right to the next laser line.
Programming Commands FETCh Measurement Instruction FETCh Measurement Instruction For information on the FETCh measurement instruction, refer to “Measurement Instructions” on page 4- 15.
Programming Commands HCOPy Subsystem HCOPy Subsystem Use the command in this subsystem to print the displayed measurement results to a printer. This subsystem has the following command hierarchy: :HCOPy [:IMMediate] [:IMMediate] Prints measurement results on a printer. Syntax :HCOPy:IMMediate Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Command Only Description Connect the printer to the Agilent 86120C’s rear- panel PARALLEL PRINTER PORT connector.
Programming Commands MEASure Measurement Instruction MEASure Measurement Instruction For information on the MEASure measurement instruction, refer to “Measurement Instructions” on page 4- 15.
Programming Commands READ Measurement Instruction READ Measurement Instruction For information on the READ measurement instruction, refer to “Measurement Instructions” on page 4- 15.
Programming Commands SENSe Subsystem SENSe Subsystem Use the SENSe commands to correct measurement results for elevation above sea level and to select between measurements in air or vacuum. You can also enter an amplitude offset.
Programming Commands SENSe Subsystem CORRection:DEVice Selects the wavelength measurement algorithm. Syntax :SENSe:CORRection:[DEVice]{?| {NARRow | BROad}} Constant Description NARRow Selects wavelength measurements for narrowband devices such as DFB lasers and modes of FP lasers. BROad Selects wavelength measurements for broadband devices such as optical filters and LEDs.
Programming Commands SENSe Subsystem CORRection:ELEVation Sets the elevation value used by the instrument to compensate for air dispersion. Syntax :SENSe:CORRection:ELEVation{?| { | MINimum | MAXimum}} is the altitude in meters. Constant Description MINimum 0m MAXimum 5000 m Attribute Summary Non- sequential command Preset State: unaffected by *RST sets this value to the minimum.
Programming Commands SENSe Subsystem CORRection:MEDium Sets the Agilent 86120C to return wavelength readings in a vacuum or standard air. Syntax :SENSe:CORRection:MEDium{?| {AIR | VACuum}} Argument Description AIR Selects wavelength values in standard air. VACuum Selects wavelength values in a vacuum.
Programming Commands SENSe Subsystem CORRection:OFFSet[:MAGNitude] Enters an offset for amplitude values. Syntax :SENSe:CORRection:OFFSet:MAGNitude{?| { | MINimum | MAXimum}} is the logarithmic units in dB. Constant Description MINimum −40.0 dB MAXimum 40.0 dB Attribute Summary Preset State: 0.0 *RST State: 0.0 SCPI Compliance: standard Query Response The query form returns the current offset setting as shown in the following example: +5.
Programming Commands SENSe Subsystem DATA? Queries the time domain samples of the input laser line. Syntax :SENSe:DATA? Attribute Summary Preset State: none SCPI Compliance: instrument specific Query Only Description Be prepared to process a large amount of data when this query is sent. The amount of data returned depends on the measurement update state of the instrument which is set using the resolution argument of an instrument function. Refer to “Measurement Instructions” on page 4- 15.
Programming Commands SENSe Subsystem Query Response The following string shows an example of the first few measurements returned by this query. +1.51367200E+000,+1.51855500E+000,+1.49902300E+000,+1.47949200E+000,+1.50488300E+00 0,+1.53320300E+000,+1.50097700E+000,+1.47265600E+000,+1.50293000E+000,+1.50781300E+0 00,+1.51171900E+000,+1.48242200E+000,+1.50097700E+000,+1.51855500E+000,+1.50683600E+ 000,+1.48632800E+000,+1.50488300E+000 Notice that only values are returned to the computer.
Programming Commands STATus Subsystem STATus Subsystem Use the commands in this subsystem to control the Agilent 86120C’s status- reporting structures. These structures provide registers that you can use to determine if certain events have occurred.
Programming Commands STATus Subsystem {OPERation | QUEStionable}:CONDition? Queries the value of the questionable or operation condition register. Syntax :STATus:{OPERation | QUEStionable}:CONDition? Query Response 0 to 32767 Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Query Only Description Use this command to read the value of the OPERation Status or QUEStionable Status registers. Refer to “Monitoring the Instrument” on page 3- 16.
Programming Commands STATus Subsystem {OPERation | QUEStionable}:ENABle Sets the enable mask for the questionable or operation event register. Syntax :STATus:{OPERation | QUEStionable}:ENABle{?| } an integer from 0 to 65535. Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Description The enable mask selects which conditions in the event register cause the summary bit in the status byte to be set.
Programming Commands STATus Subsystem {OPERation | QUEStionable}[:EVENt] Queries the contents of the questionable or operation event registers. Syntax :STATus:{OPERation | QUEStionable}:EVENt? Query Response 0 to 32767 Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Query Only Description The response will be a number from 0 to 32767 indicating which bits are set. Reading the register clears the register.
Programming Commands STATus Subsystem {OPERation | QUEStionable}:NTRansition Selects bits in the event register which can be set by negative transitions of the corresponding bits in the condition register. Syntax :STATus:OPERation:NTRansition{?| } an integer from 0 to 65535.
Programming Commands STATus Subsystem {OPERation | QUEStionable}:PTRansition Selects bits in the event register which can be set by positive transitions of the corresponding bits in the condition register. Syntax :STATus:OPERation:PTRansition{?| } an integer from 0 to 65535.
Programming Commands STATus Subsystem PRESet Presets the enable registers and the PTRansition and NTRansition filters. Syntax :STATus:PRESet Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Command Only Description The PRESet command is defined by SCPI to affect the enable register. If you want to clear all event registers and queues, use the *CLS command. Table 4-18.
Programming Commands SYSTem Subsystem SYSTem Subsystem The commands in this subsystem have the following command hierarchy: :SYSTem :ERRor? :HELP :HEADers? :PRESet :VERSion? 4-97
Programming Commands SYSTem Subsystem ERRor Queries an error from the error queue. Syntax :SYSTem:ERRor? Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Query Only Description The Agilent 86120C has a 30 entry error queue. The queue is a firstin, first- out buffer. Repeatedly sending the query :SYSTEM:ERROR? returns the error numbers and descriptions in the order in which they occur until the queue is empty.
Programming Commands SYSTem Subsystem HELP:HEADers? Queries a listing of all the remote programming commands available for the Agilent 86120C. Syntax :SYSTem:HELP:HEADers? Attribute Summary Preset State: none *RST State: none SCPI Compliance: instrument specific Query Only Description The returned ASCII string of commands is in the IEEE 488.2 arbitraryblock data format. The first line indicates the total number of bytes returned to the computer.
Programming Commands SYSTem Subsystem PRESet Performs the equivalent of pressing the front- panel PRESET key. Syntax :SYSTem:PRESet Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Command Only Description The instrument state is set according to the settings shown in the following table. Table 4-19.
Programming Commands SYSTem Subsystem Table 4-19.
Programming Commands SYSTem Subsystem VERSion Queries the version of SCPI that the Agilent 86120C complies with. Syntax :SYSTem:VERSion Attribute Summary Preset State: none *RST State: none SCPI Compliance: standard Query Only Description The SCPI version used in the Agilent 86120C is 1995.0. Table 4-20. SCPI Version Numbers SCPI Version Instrument Serial Prefix 1995.
Programming Commands TRIGger Subsystem TRIGger Subsystem The SCPI definition defines the TRIGger subsystem to include ABORt, ARM, INITiate, and TRIGger commands. The Agilent 86120C has no ARM or TRIGger commands.
ABORt Halts the current measurement sequence and places the instrument in the idle state. Syntax :ABORt Attribute Summary Preset State: not affected SCPI Compliance: standard Command Only Description If the instrument is configured for continuous measurements, a new measurement sequence will begin. Otherwise, the instrument stays in the idle state until a new measurement is initiated.
Programming Commands TRIGger Subsystem INITiate:CONTinuous Selects single or continuous measurement acquisition. Syntax :INITiate:CONTinuous{?| {ON | OFF | 1 | 0}} Attribute Summary Non- sequential command Preset State: on *RST State: off SCPI Compliance: standard Description When on is specified, the instrument continuously measures the input spectrum.
Programming Commands TRIGger Subsystem INITiate[:IMMediate] Initiates a new measurement sequence. Syntax :INITiate:IMMediate Attribute Summary Non- sequential command Preset State: none SCPI Compliance: standard Command Only Non-sequential command Always use an *OPC? query or a *WAI command to ensure that this command has the time to complete before sending any more commands to the instrument.
Programming Commands UNIT Subsystem UNIT Subsystem The only command provided in this subsystem is the POWer command as shown in the following command hierarchy: :UNIT [:POWer] [:POWer] Sets the power units to watts (linear) or dBm (logarithmic).
Programming Commands UNIT Subsystem 4-108
5 Test Test Test Test Test 1. 2. 3. 4. 5.
Performance Tests Performance Tests Performance Tests The procedures in this chapter test the Agilent 86120C’s performance using the specifications listed in Chapter 6, “Specifications and Regulatory Information” as the performance standard. All of the tests are done manually without the aid of a computer. None of these tests require access to the interior of the instrument. Test Test Test Test Test 1. 2. 3. 4. 5.
Performance Tests Test 1. Absolute Wavelength Accuracy Test 1. Absolute Wavelength Accuracy Description Wavelength accuracy is verified using traceable light sources such as the following devices: • Stable lasers • Gas lamps • HeNe gas lasers CAUTION Do not exceed +18 dBm source power. The Agilent 86120C’s input circuitry can be damaged when total input power exceeds 18 dBm. Procedure Use three or four light standards that cover the Agilent 86120C’s wavelength range.
Performance Tests Test 2. Sensitivity Test 2. Sensitivity Description Sensitivity is verified using the following devices: • Optical power meter • Optical attenuator • 1310 nm and 1550 nm lasers (>0 dBm output power) CAUTION Do not exceed +18 dBm source power. The Agilent 86120C’s input circuitry can be damaged when total input power exceeds 18 dBm. Procedure Perform the following procedure first using the 1310 nm laser and then repeat the steps using the 1550 nm laser.
Performance Tests Test 3. Polarization Dependence Test 3. Polarization Dependence Description Polarization Dependence is verified using the following devices: • 1310 nm and 1550 nm DFB lasers • Optical attenuator • Agilent 11896A polarization controller CAUTION Do not exceed +18 dBm source power. The Agilent 86120C’s input circuitry can be damaged when total input power exceeds 18 dBm.
Performance Tests Test 4. Optical Input Return Loss Test 4. Optical Input Return Loss Description Input return loss is verified using the following devices: • Agilent 8153A lightwave multimeter • Agilent 81553SM 1550 nm Fabry- Perot laser, SM 9/125 µm source module • Agilent 81534A return loss module Procedure Standard instruments (flat contacting connectors) 1 Turn the source module’s output off.
Performance Tests Test 4. Optical Input Return Loss and Regulatory Information”. Procedure Option 022 instruments (angled contacting connectors) 1 Turn the source module’s output off. 2 Connect a single- mode patchcord between the source module’s optical output and the return loss module’s INPUT SOURCE connector. 3 Set the return loss module’s wavelength to 1550 nm, and select an average time of 1 second. 4 Locate an HMS- 10/HRL to FC/APC (angled FC) patchcord.
Performance Tests Test 4. Optical Input Return Loss FC/APC patchcord loss The effect of having loss in the FC/APC patchcord 1 to 2 connector pair is to under measure the return loss by twice the FC/APC patchcord 1 to 2 loss. For example, if this connector pair loss is 0.5 dB, then the actual return loss caused by the 14.6 dB Fresnel reflection is 15.6 dB, but we enter 14.6 dB as an R value. Then, if the device under test return loss is exactly 40 dB below that of the 14.
Performance Tests Test 5. Amplitude Accuracy and Linearity Test 5. Amplitude Accuracy and Linearity Equipment Amplitude linearity is performed using the following devices: • • • • 1550 nm DFB lasers Optical attenuator Agilent 11896A polarization controller Optical power meter Procedure Polarization sensitivity To ensure measurement accuracy, minimize the movement of any fiber-optic cables during this procedure. Moving cables causes polarization changes which affect amplitude measurements.
Performance Tests Test 5. Amplitude Accuracy and Linearity completely filled in. 10 Disconnect the fiber- optic cable from the optical power meter and connect it to the Agilent 86120C’s OPTICAL INPUT connector. 11 Set the optical attenuator for the value that you recorded in Step 8. 12 Place the polarization controller in the auto scan mode. 13 Press the Agilent 86120C’s front- panel Preset key. 14 Press List by Power, Appl’s, and then DRIFT.
Performance Tests Test 5. Amplitude Accuracy and Linearity Table 5-21.
6 Definition of Terms 6- 3 Specifications—NORMAL Update Mode 6- 5 Specifications—FAST Update Mode 6- 8 Operating Specifications 6- 11 Laser Safety Information 6- 12 Compliance with Canadian EMC Requirements Declaration of Conformity 6- 14 Product Overview 6- 15 6- 13 Specifications and Regulatory Information
Specifications and Regulatory Information Specifications and Regulatory Information Specifications and Regulatory Information This chapter lists specification and characteristics of the instrument. The distinction between these terms is described as follows: • Specifications describe warranted performance over the temperature range 0°C to +55°C and relative humidity <95% (unless otherwise noted).
Specifications and Regulatory Information Definition of Terms Definition of Terms Wavelength Range refers to the allowable wavelength range of the optical input signal. Absolute accuracy indicates the maximum wavelength error over the allowed environmental conditions. The wavelength accuracy is based on fundamental physical constants, which are absolute standards not requiring traceability to artifacts kept at national standards laboratories. Two He-Ne gas lasers are used.
Specifications and Regulatory Information Definition of Terms of one laser line. Polarization Dependence indicates the maximum displayed power variation as the polarization of the input signal is varied. Display Resolution indicates the minimum incremental change in displayed power. Sensitivity Sensitivity is defined as the minimum power level of a single laser-line input to measure wavelength and power accurately.
Specifications and Regulatory Information Specifications—NORMAL Update Mode Specifications—NORMAL Update Mode Each laser line is assumed to have a linewidth (including modulation sidebands) of less than 5 GHz. All specifications apply when the instrument is in the following modes: • NORMAL update mode unless noted. Refer to “Measurement rate” on page 2- 13. • Configured to measure narrowband devices. Specifications do not apply when the instrument is configured to measure broadband devices.
Specifications and Regulatory Information Specifications—NORMAL Update Mode Amplitude Calibration accuracy at calibration wavelengths ±0.5 dB (at 1310 and 1550 nm ±30 nm) Flatness, ±30 nm from any wavelength 1270-1600 nm (characteristic) ±0.2 dB 1270-1650 nm (characteristic) ±0.5 dB Linearity, 1270 nm to 1600 nm, lines above –30 dBm ±0.3 dB Polarization dependence 1270-1600 nm ±0.5 dB 1600-1650 nm (characteristic) ±1.0 dB Display resolution 0.
Specifications and Regulatory Information Specifications—NORMAL Update Mode Input Return Loss With straight contactconnectors 35 dB With angled contact connectors (Option 022) 50 dB Measurement Cycle Time Normal update mode (characteristic) 1.
Specifications and Regulatory Information Specifications—FAST Update Mode Specifications—FAST Update Mode Each laser line is assumed to have a linewidth (including modulation sidebands) of less than 10 GHz. All specifications apply when the instrument is in the following modes: • FAST update mode unless noted. Refer to “Measurement rate” on page 2- 13. • Configured to measure narrowband devices. Specifications do not apply when the instrument is configured to measure broadband devices.
Specifications and Regulatory Information Specifications—FAST Update Mode Amplitude Calibration accuracy at calibration wavelengths ±0.5 dB (at 1310 and 1550 nm ±30 nm) Flatness, ±30 nm from any wavelength 1270-1600 nm (characteristic) ±0.2 dB 1270-1650 nm (characteristic) ±0.5 dB Linearity, 1270 nm to 1600 nm, lines above –30 dBm ±0.3 dB Polarization dependence 1270-1600 nm ±0.5 dB 1600-1650 nm (characteristic) ±1.0 dB Display resolution 0.
Specifications and Regulatory Information Specifications—FAST Update Mode Input Return Loss With flat contacting connectors 35 dB With angled contacting connectors (Option 022) 50 dB Measurement Cycle Time Fast update mode (characteristic) 0.
Specifications and Regulatory Information Operating Specifications Operating Specifications Operating Specifications Use indoor Power: 70 W max Voltage 100 / 115 / 230 / 240 V ~ Frequency 50 / 60 Hz Altitude Up to 2000 m (~ 6600 ft) Operating temperature 0°C to +55°C Maximum relative humidity 80% for temperatures up to 31°C decreasing linearly to 50% relative humidity at 40°C Weight 8.5 kg (19 lb) Dimensions (H × W × D) 140 × 340 × 465 mm (5.5 × 13.4 × 18.
Specifications and Regulatory Information Laser Safety Information Laser Safety Information The light sources specified by this user guide are classified according to IEC 60825-1 (2001). The light sources comply with 21 CFR 1040.10 except for deviations pursuant to Laser Notice No. 50, dated 2001-July-26. Laser Safety Laser type LED Wavelength 1200-1650nm Max. CW output power * 1 nW Beam waist diameter 10 µm Numeric aperture 0.1 Laser class according to IEC 60825-1 (2001) 1 Max.
Specifications and Regulatory Information Compliance with Canadian EMC Requirements Compliance with Canadian EMC Requirements This ISM device complies with Canadian ICES-001. Cet appareil ISM est conforme à la norme NMB-001 du Canada.
Specifications and Regulatory Information Declaration of Conformity Declaration of Conformity 6-14
Specifications and Regulatory Information Product Overview Product Overview Front view of instrument Rear view of instrument 6-15
Specifications and Regulatory Information Product Overview 6-16
7 Instrument Preset Conditions 7-2 Menu Maps 7-4 Error Messages 7-11 Front-Panel Fiber-Optic Adapters 7-17 Power Cords 7-18 Agilent Technologies Service Offices 7-18 Reference
Reference Reference Reference Instrument Preset Conditions Table 5-22.
Reference Instrument Preset Conditions Table 5-22.
Reference Menu Maps Menu Maps This section provides menu maps for the Agilent 86120C softkeys. The maps show which softkeys are displayed after pressing a front-panel key; they show the relationship between softkeys. The softkeys in these maps are aligned vertically instead of horizontally as on the actual display. This was done to conserve space and to make the maps easier to interpret.
Reference Menu Maps Appl’s Menu 7-5
Reference Menu Maps Display Avg WL Menu There is no menu associated with this key. Measurement Cont Menu There is no menu associated with this key.
Reference Menu Maps Display List by WL Menu Delta On Menu 7-7
Reference Menu Maps Delta Off Menu Display Peak WL and System Preset Menus Measurement Single Menu There is no menu associated with this key.
Reference Menu Maps System Print Menu 7-9
Reference Menu Maps System Setup Menu 7-10
Reference Error Messages Error Messages In this section, you’ll find all the error messages that the Agilent 86120C can display on its screen. Table 5-23 on page 7-11 lists all instrument-specific errors. Table 5-24 on page 7-14 lists general SCPI errors. Table 5-23.
Reference Error Messages Table 5-23.
Reference Error Messages Table 5-23.
Reference Error Messages Table 5-24.
Reference Error Messages Table 5-24. General SCPI Error Messages (2 of 3) Error Number Description –158 “String data not allowed“ –161 “Invalid block data“ –168 “Block data not allowed“ –170 “Expression error“ –171 “Invalid expression“ –178 “Expression data not allowed“ –200 “Execution error“ –211 “Trigger ignored” Caused by sending the *TRG command when the instrument is already taking a measurement or when the instrument is in continuous measurement mode.
Reference Error Messages Table 5-24. General SCPI Error Messages (3 of 3) Error Number Description –310 “System error“ –321 “Out of memory” –350 “Too many errors“ –400 “Query error“ –410 “Query INTERRUPTED“ –420 “Query UNTERMINATED“ –430 “Query DEADLOCKED“ –440 “Query UNTERMINATED after indef resp“ Query was unterminated after an indefinite response.
Reference Front-Panel Fiber-Optic Adapters Front-Panel Fiber-Optic Adapters Front Panel Fiber-Optic Adapter Description Agilent Part Number Diamond HMS-10 81000AI FC/PCa 81000FI D4 81000GI SC 81000KI DIN 81000SI ST 81000VI Biconic 81000WI a. The FC/PC is the default front-panel optical connector.
Reference Power Cords Power Cords Plug Type Cable Part No. 250V 8120-1351 United Kingdom, Cyprus, Nigeria, Zimbabwe, Singapore 250V 8120-1369 Australia, New Zealand, China 250V 8120-1689 East and West Europe, Saudi Arabia, So.
Reference Agilent Technologies Service Offices Before returning an instrument for service, call the Agilent Technologies Instrument Support Center at +1 (877) 447 7278, visit the Test and Measurement Web Sites by Country page at http://www.agilent.com/comms/techsupport, select your country and enter the “Technical Support” link, or call one of the numbers listed below.
Index ASNR, 48 Numerics softkey, 28 AVERAGE annotation, 7 average wavelength, iii, 7 Avg WL key, 7, 8 1 nm annotation, 27, 30 A ABORt programming command, 104 ABORT softkey, 39 ac power cables, 6 adapters, fiber optic, 17 adding parameters, 25 address.
Index *CLS, 21, 3 CM –1 softkey, 13 Cmd_opc subroutine, 29 colon, 25 commands combining, 24 common, 23 measurement instructions, 23 non sequential, 12, 29, 34, 35, 37, 38, 39, 40, 41, 42, 43, 85, 105, 106 standard SCPI, 23 termination, 27 common commands *CLS (clear status), 3 *ESE (event status enable), 28, 3 *ESR (event status register), 5 *IDN (identification number), 29, 6 *OPC (operation complete), 29, 7 *RST (reset), 29, 8 *SRE (service request enable), 10 *STB (status byte), 12 *TRG (trigger), 13 *T
Index increase source accuracy, 41 measure DFB laser, 30 measure SNR, 39 measure WDM channel drift, 34 measure WDM channel separation, 37 measure WDM channels, 32 external attenuation, 36 F Fabry-Perot lasers, iii, 9 measuring, 15, 31 fast fourier transform, 29 FAST softkey, 14, 9, 88 FETCh measurement instruction, 15 fiber optics adapters, 17 care of, v cleaning connections, 40 connectors, covering, 12 firmware version displayed, 7 over GPIB, 6 flatness, 3, 6, 9 FNIdentity function, 29 FP TEST softkey, 3
Index specifications, 11 linewidth, 2 List by Power menu map, 6 mode, 9 softkey, 6, 23 List by WL key, 6 menu map, 7 mode, 9 softkey, 6, 23 LOCAL softkey, 3 long form commands, 23 lowercase letters, 24 M M annotation, 4 MAGNitude programming command, 87 MAX NUMBER OF SIGNALS FOUND, 17 maximum power input, iv MAXimum programming command, 76 MAX-MIN softkey, 23 MEASure measurement instruction, 30, 32, 15 measurement accuracy, 3 air, in, 37 AM modulation, 15, 34 audio modulation, effects of, 15, 34 average w
Index O Off key, 20 menu map, 8 On key, 20 menu map, 7 *OPC, 29, 3, 7 OPTICAL INPUT connector, iii, vi, 14 output queue, 22, 27 P packaging for shipment, 13 PARALLEL PRINTER PORT connector, 6, 39 parameters, adding, 25 PEAK annotation, 4 softkey, 5, 28 peak definition of, 15 excursion, 9, 16 power, iii, 4 threshold limit, 15, 17, 35 wavelength, iii, 4 Peak WL key, 4 menu map, 8 softkey, 4, 23 performance tests, 2 PEXCursion programming command, 33 PK EXC softkey, 17 PK THLD softkey, 17 POINts? programming
Index return loss, 4, 7, 10 returning data, 27 for service, 11 RF modulation, 35 RIGHT programming command, 78 *RST, 3, 29, 8 S S/N AUTO annotation, 25 S/N softkey, 28 S/N USER annotation, 25 safety, vi, vii laser classification, vii symbols, iii sales and service offices, 18 SCALar programming command, 15 SCPI (standard commands for programmable instruments) standard, 2 syntax rules, 23 SELECT softkey, 6, 19 selectivity, 4, 6, 9 semicolon, 23 sending common commands, 25 SENSe subsystem, 83 sensitivity, 4
Index units of measure, 12 UNITS softkey, 12 up-arrow softkey, 6 UPDATE softkey, 14 uppercase letters, 24 USER softkey, 28 USER WL softkey, 28 UW softkey, 13 V VAC annotation, 37 VACuum programming command, 86 VACUUM softkey, 9, 38 vacuum, measurements in, 37 VERSion programming command, 102 W *WAI, 14 wave number, 13 wavelength definition of, 3 input range, 2 peak, 4 range, 37 separation, 18 specifications, 5, 8 WAVelength programming command, 21, 52, 71 WDM flatness, 21 system, 18 white space character
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