Agilent 86120B Multi-Wavelength Meter User’s Guide
© Copyright Agilent Technologies 2000 All Rights Reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowed under copyright laws. Agilent Part No. 86120-90033 Printed in USA February 2000 Agilent Technologies Lightwave Division 1400 Fountaingrove Parkway Santa Rosa, CA 95403-1799, USA (707) 577-1400 Notice. The information contained in this document is subject to change without notice.
The Agilent 86120B—At a Glance The Agilent 86120B—At a Glance The Agilent 86120B Multi-Wavelength Meter measures the wavelength and optical power of laser light in the 700-1650 nm wavelength range. Because the Agilent 86120B 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 86120B—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 86120B’s display. CAUTION The input circuitry of the Agilent 86120B can be damaged when total input power levels exceed +18 dBm. To prevent input damage, this specified level must not be exceeded.
The Agilent 86120B—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 86120B’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 86120B, refer to “Cleaning Connections for Accurate Measurements” on page 1-13.
General Safety Considerations General Safety Considerations This product has been designed and tested in accordance with IEC Publication 1010, Safety Requirements for Electronic Measuring Apparatus, 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 FDA Laser Class I (IEC Laser Class 1).
General Safety Considerations WARNING To prevent electrical shock, disconnect the Agilent 86120B from mains before cleaning. Use a dry cloth or one slightly dampened with water to clean the external case parts. Do not attempt to clean internally. WARNING This is a Safety Class 1 product (provided with a protective earthing ground incorporated in the power cord). The mains plug shall only be inserted in a socket outlet provided with a protective earth contact.
General Safety Considerations temperature of the product by 4°C for every 100 watts dissipated in the cabinet. If the total power dissipated in the cabinet is greater than 800 watts, then forced convection must be used. CAUTION Always use the three-prong ac power cord supplied with this instrument. Failure to ensure adequate earth grounding by not using this cord may cause instrument damage.
Contents The Agilent 86120B—At a Glance iii General Safety Considerations vi 1 Getting Started Step 1. Inspect the Shipment 1-3 Step 2. Check the Fuse 1-5 Step 3. Connect the Line-Power Cable 1-6 Step 4. Connect a Printer 1-7 Step 5. Turn on the Agilent 86120B 1-8 Step 6. Enter Your Elevation 1-10 Step 7. Select Medium for Wavelength Values 1-11 Step 8.
Contents Lists of Commands 4-43 5 Programming Commands Common Commands 5-3 Measurement Instructions 5-15 CALCulate1 Subsystem 5-26 CALCulate2 Subsystem 5-31 CALCulate3 Subsystem 5-43 CONFigure Measurement Instruction 5-64 DISPlay Subsystem 5-64 FETCh Measurement Instruction 5-67 HCOPy Subsystem 5-68 MEASure Measurement Instruction 5-68 READ Measurement Instruction 5-69 SENSe Subsystem 5-69 STATus Subsystem 5-74 SYSTem Subsystem 5-79 TRIGger Subsystem 5-84 UNIT Subsystem 5-86 6 Performance Tests Test 1.
Contents Power Cords 8-16 Agilent Technologies Service Offices 8-18 Contents-3
1 Step 1. Inspect the Shipment 1-3 Step 2. Check the Fuse 1-5 Step 3. Connect the Line-Power Cable 1-6 Step 4. Connect a Printer 1-7 Step 5. Turn on the Agilent 86120B 1-8 Step 6. Enter Your Elevation 1-10 Step 7. Select Medium for Wavelength Values 1-11 Step 8.
Getting Started Getting Started Getting Started The instructions in this chapter show you how to install your Agilent 86120B. You should be able to finish these procedures in about ten to twenty minutes. After you’ve completed this chapter, continue with Chapter 2, “Using the Multi-Wavelength Meter”. Refer to Chapter 7, “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 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 1. Inspect the Shipment Table 1-1.
Getting Started Step 2. Check the Fuse Step 2. Check the Fuse 1 Locate the line-input connector on the instrument’s rear panel. 2 Disconnect the line-power cable if it is connected. 3 Use a small flat-blade screwdriver to open the pull-out fuse drawer. 4 Verify that the value of the line-voltage fuse in the pull-out drawer is correct. The recommended fuse is an IEC 127 5×20 mm, 6.3A, 250 V, Agilent Technologies part number 2110-0703.
Getting Started Step 3. Connect the Line-Power Cable Step 3. Connect the Line-Power Cable WARNING This is a Safety Class 1 Product (provided with a protective earthing ground incorporated in the power cord). 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 4. 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 86120B to ac power outlets unique to specific geographic areas. The cable appropriate for the area to which the Agilent 86120B is originally shipped is included with the unit. The cable shipped with the instrument also has a right-angle connector so that the Agilent 86120B can be used while sitting on its rear feet.
Getting Started Step 5. Turn on the Agilent 86120B Step 5. Turn on the Agilent 86120B CAUTION The front panel LINE switch disconnects the mains circuits from the mains supply after the EMC filters and before other parts of the instrument. 1 Press the front-panel LINE key. After approximately 20 seconds, the display should look similar to the following figure: 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. Turn on the Agilent 86120B Instrument firmware version When the instrument is first turned on, the display briefly shows the instrument’s firmware version number. In the unlikely event that you have a problem with the Agilent 86120B, you may need to indicate this number when communicating with Agilent Technologies. There is no output laser aperture The Agilent 86120B does not have an output laser aperture.
Getting Started Step 6. Enter Your Elevation Step 6. Enter Your Elevation In order for your Agilent 86120B 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 7. Select Medium for Wavelength Values Step 7. Select Medium for Wavelength Values Because wavelength varies with the material that the light passes through, the Agilent 86120B 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 8. Turn Off Wavelength Limiting Step 8. Turn Off Wavelength Limiting After the Preset key is pressed, the input wavelength range is limited to measuring lasers between 1200 nm and 1650 nm. You can easily expand the input range to the full 700 nm to 1650 nm range with the following steps: 1 Press the Preset key. 2 Press the Setup key. 3 Press the WL LIM softkey. 4 Press LIM OFF to remove the limits on wavelength range.
Getting Started 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.
Getting Started Cleaning Connections for Accurate Measurements tions 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 1-1. Basic components of a connector. Over the last few years, the FC/PC style connector has emerged as the most popular connector for fiber-optic applications.
Getting Started Cleaning Connections for Accurate Measurements Figure 1-2. 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 1-3. Figure 1-3. 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.
Getting Started 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.
Getting Started 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 1-4. Clean, problem-free fiber end and ferrule. Figure 1-5. Dirty fiber end and ferrule from poor cleaning.
Getting Started Cleaning Connections for Accurate Measurements Figure 1-6. 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.
Getting Started Cleaning Connections for Accurate Measurements • 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. Frequently measure the return loss of the connector to check for degradation, and clean every connector, every time. All connectors should be treated like the high-quality lens of a good camera.
Getting Started 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.
Getting Started Cleaning Connections for Accurate Measurements Table 1-3. Dust Caps Provided with Lightwave Instruments Item Agilent Technologies Part Number Laser shutter cap 08145-64521 FC/PC dust cap 08154-44102 Biconic dust cap 08154-44105 DIN dust cap 5040-9364 HMS10/dust cap 5040-9361 ST dust cap 5040-9366 To clean a non-lensed connector CAUTION Do not use any type of foam swab to clean optical fiber ends. Foam swabs can leave filmy deposits on fiber ends that can degrade performance.
Getting Started Cleaning Connections for Accurate Measurements CAUTION Do not shake, tip, or invert compressed air canisters, because this releases particles in the can into the air. Refer to instructions provided on the compressed air canister. 7 As soon as the connector is dry, connect or cover it for later use. If the performance, after the initial cleaning, seems poor try cleaning the connector again. Often a second cleaning will restore proper performance.
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 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. • Whether instrument is vibration-sensitive. • Instrument settings required to reproduce the problem. • Performance data. • Company name and return address. • Name and phone number of technical contact person.
Getting Started Returning the Instrument for Service Sealed Air Corporation (Commerce, California 90001). Air Cap looks like a plastic sheet filled with air bubbles. Use the pink (antistatic) Air Cap™ to reduce static electricity. Wrapping the instrument several times in this material will protect the instrument and prevent it from moving in the carton. 4 Seal the carton with strong nylon adhesive tape. 5 Mark the carton “FRAGILE, HANDLE WITH CARE”. 6 Retain copies of all shipping papers.
2 Displaying Wavelength and Power 2-3 Changing the Units and Measurement Rate 2-13 Defining Laser-Line Peaks 2-16 Measuring Laser Separation 2-20 Measuring Modulated Lasers 2-23 Measuring Total Power Greater than 10 dBm 2-25 Calibrating Measurements 2-26 Printing Measurement Results 2-28 Using the Multi-Wavelength Meter
Using the Multi-Wavelength Meter Using the Multi-Wavelength Meter Using the Multi-Wavelength Meter 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: • 700 nm to 1650 nm maximum input wavelength range The range is normally limited from 1200 nm to 1650 nm. To use the full range, refer to “Measuring lasers between 700 nm and 1200 nm” on page 2-8 and to “To use the full wavelength range” on page 2-8.
Using the Multi-Wavelength Meter Displaying Wavelength and Power Displaying 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.
Using the Multi-Wavelength Meter Displaying Wavelength and Power Peak WL mode When Peak WL is pressed, the display shows the largest amplitude line in the spectrum. This is the peak wavelength mode. 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. Display after “Peak WL” key pressed In addition to the digital readouts, there is a power bar.
Using the Multi-Wavelength Meter Displaying 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.
Using the Multi-Wavelength Meter Displaying 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. In list by wavelength mode, the signals are displayed in order from shortest to longest wavelengths. The Agilent 86120B can measure up to 100 laser lines simultaneously. Use the and softkeys to move the cursor through the list of signals; the list can contain up to 100 entries.
Using the Multi-Wavelength Meter Displaying Wavelength and Power 4 Press List by Power to display the laser lines in order of decreasing amplitudes. Total power and average wavelength In the third available display mode, the Agilent 86120B 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.
Using the Multi-Wavelength Meter Displaying Wavelength and Power 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. Measuring lasers between 700 nm and 1200 nm After the Preset key is pressed, the input wavelength range is limited to measuring lasers between 1200 nm and 1650 nm.
Using the Multi-Wavelength Meter Displaying Wavelength and Power Limiting the wavelength range The wavelength range of measurement can be limited with the wavelength limit function. Both start and stop wavelengths can be chosen. The units of wavelength start and stop are the same as the currently selected wavelength units. If wavelength units are later changed, the start and stop wavelength units will change accordingly.
Using the Multi-Wavelength Meter Displaying Wavelength and Power Measuring broadband devices and chirped lasers When first turned on (or the green Preset key is pressed), the Agilent 86120B 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.
Using the Multi-Wavelength Meter Displaying 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.
Using the Multi-Wavelength Meter Displaying 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 8-1 on page 8-2. If drift measurements or an application (such as signalto-noise) is on when an instrument state is saved, it is off when that state is recalled.
Using the Multi-Wavelength Meter 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 2-13 Measurement rate 2-14 Continuous or single measurements 2-15 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.
Using the Multi-Wavelength Meter 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 terahertz • 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 86120B makes a measurement and displays the results about once every second.
Using the Multi-Wavelength Meter Changing the Units and Measurement Rate Continuous or single measurements The Agilent 86120B continuously measures the input spectrum at the frontpanel OPTICAL INPUT connector. Whenever measurements are being acquired, an asterisk (*) is displayed in the display’s upper right corner. When you switch between normal and fast update modes the rate that the asterisk blinks changes.
Using the Multi-Wavelength Meter Defining Laser-Line Peaks Defining Laser-Line Peaks The Agilent 86120B 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.
Using the Multi-Wavelength Meter Defining Laser-Line Peaks 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. Examples of valid In the following figure, three laser lines are identified: responses ➀, ➂, and ➃. and invalid signals Response ➁ is not identified because it is below the peak threshold.
Using the Multi-Wavelength Meter Defining Laser-Line Peaks Limiting the input The Agilent 86120B’s preset condition limits the wavelength measurement wavelength range range from 1200 nm to 1650 nm. You can expand the wavelength range to cover the entire 700 nm to 1650 nm range. Although wavelength range limiting reduces the number of laser lines found, its main purpose is to eliminate the identification of second harmonic distortion products as described in the following sidebar.
Using the Multi-Wavelength Meter Defining Laser-Line Peaks To define laser-line peaks 1 Press the Setup key. 2 Press the THRSHLD softkey. 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.
Using the Multi-Wavelength Meter 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-divisionmultiplexed (WDM) systems where channel spacing must be adhered to. The Agilent 86120B can display the wavelength and amplitude of any laser line relative to another.
Using the Multi-Wavelength Meter 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 86120B 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.
Using the Multi-Wavelength Meter 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.
Using the Multi-Wavelength Meter Measuring Modulated Lasers Measuring Modulated Lasers Lasers modulated A laser that is amplitude modulated at low frequencies (for example, moduat low frequencies lated 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.
Using the Multi-Wavelength Meter 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.
Using the Multi-Wavelength Meter 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 86120B 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.
Using the Multi-Wavelength Meter 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 86120B 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.
Using the Multi-Wavelength Meter 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 86120B 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.
Using the Multi-Wavelength Meter 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.
Using the Multi-Wavelength Meter Printing Measurement Results To create a hardcopy 1 Connect the printer to the Agilent 86120B’s rear-panel PARALLEL PRINTER PORT connector. 2 Press Print. You can use the ABORT and CONT softkey to stop and restart a print job that is in progress.
3 Measuring Signal-to-Noise Ratios 3-3 Measuring Signal-to-Noise Ratios with Averaging 3-7 Measuring Laser Drift 3-9 Measuring Coherence Length 3-12 Measurements Applications
Measurements Applications Measurements Applications Measurements Applications In this chapter, you’ll learn how to make a variety of fast, accurate measurements using the measurement tools accessed by pressing the Appl’s key.
Measurements Applications 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-to-noise and bit error rate. The Agilent 86120B displays signal-to-noise measurements in the third column. For example, the selected signal in the following figure has a signalto-noise ratio of 30.0 dB.
Measurements Applications Measuring Signal-to-Noise Ratios Location of noise measurements Automatic interpolation When the signal-to-noise “auto” function is selected, the Agilent 86120B 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.
Measurements Applications Measuring Signal-to-Noise Ratios User-entered wavelength When the signal-to-noise “user” function is selected, the Agilent 86120B 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.
Measurements Applications Measuring Signal-to-Noise Ratios 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. Use the softkey to select the digit that requires editing. Use the and softkeys to change the value. c Press RETURN.
Measurements Applications 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.
Measurements Applications Measuring Signal-to-Noise Ratios with Averaging During a signal-to-noise with averaging measurement, the display indicates S/N A xx, where A indicates averaging and xx is the number of 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.
Measurements Applications Measuring Laser Drift Measuring Laser Drift In this section, you’ll learn how the Agilent 86120B 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 86120B keeps track of each laser line’s initial, current, minimum, and maximum values and displays their differences relative to itself.
Measurements Applications Measuring Laser Drift If measurement updating stops or the values become blanked If, in the middle of a measurement, the number of laser lines present changes, the measurement stops until the original number of lines returns. You’ll notice that a CLEAR softkey appears and one of the following message is displayed: E46 NUM LINES < NUM REFS E47 NUM LINES > NUM REFS To view the data measured before the conditions changed, press CLEAR and then MAXMIN.
Measurements Applications Measuring Laser Drift 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. Display shows the total drift from the reference since the drift measurement was started. Values represent the minimum wavelength and power drift values subtracted from the maximum drift values.
Measurements Applications Measuring Coherence Length Measuring Coherence Length Coherence length is a measure of the distance over which a laser’s light retains the phase relationships of its spectrum. The Agilent 86120B measures coherence length of Fabry-Perot semiconductor diode lasers. The Agilent 86120B cannot measure coherence length of light emitting diodes (LEDs) or distributed feedback (DFB) lasers.
Measurements Applications Measuring Coherence Length Coherence length (Lc) The interferogram of the laser being tested is sampled and the envelope of the interferogram is found. This envelope has peaks (regions of high fringe visibility) at zero optical path delay and at delays equal to multiples of the laser cavity round-trip optical length. This is shown in the following figure of the interferogram envelope: The amplitudes of the peaks decreases exponentially from the largest peak at zero path delay.
Measurements Applications Measuring Coherence Length Alpha factor The alpha factor is defined as the height of the first envelope peak away from zero path delay relative to the height of the envelope peak at zero path delay. The alpha factor is always between 0 and 1. The smaller the alpha factor, the shorter the coherence length.
4 Addressing and Initializing the Instrument 4-3 To change the GPIB address 4-3 Making Measurements 4-5 Commands are grouped in subsystems 4-7 Measurement instructions give quick results 4-9 The format of returned data 4-15 Monitoring the Instrument 4-16 Status registers 4-16 Queues 4-21 Reviewing SCPI Syntax Rules 4-23 Example Programs 4-29 Example 1. Measure a DFB laser 4-31 Example 2. Measure WDM channels 4-33 Example 3. Measure WDM channel drift 4-35 Example 4.
Programming Programming Programming This chapter explains how to program the Agilent 86120B. 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 HP®1 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 86120B’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. To change the GPIB address 1 Press the Setup key. 2 Press MORE twice, then GPIB. 3 Use the and softkeys to change the GPIB address. 4 Press RETURN.
Programming Addressing and Initializing the Instrument gramming control, it should be in the single measurement acquisition mode. This is automatically accomplished when the *RST common command is used. The *RST command initializes the instrument to a preset state: CLEAR 720 OUTPUT 720;”*RST” 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.
Programming Making Measurements Making Measurements Making measurements remotely involves changing the Agilent 86120B’s settings, performing a measurement, and then returning the data to the computer. The simplified block diagram of the Agilent 86120B 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 WLIMit:STARt to 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 86120B commands are grouped in the following subsystems. You’ll find a description of each command in Chapter 5, “Programming Commands”. Subsystem Measurement Instructions Purpose of Commands Perform frequency, wavelength, wavenumber, and coherence length measurements. CALCulate1 Queries uncorrected frequency-spectrum data. CALCulate2 Queries corrected peak data and sets wavelength limits.
Programming Making Measurements Table 4-1.
Programming Making Measurements Measurement instructions give quick results The easiest way to measure wavelength, frequency, power, or coherence length 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 5-15. Each measurement instruction has an argument that controls the measurement update rate.
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 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, ARRay command causes an instrument to take multiple measurements. (A parameter indicates the number of measurements to take.) However, the Agilent 86120B’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 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 nonsequential commands to ensure that your programs execute properly. For example, suppose that you wanted to set the elevation correction value and then send an :INIT:IMM command. The following programming fragment results in an error –213 “Init ignored”.
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 additionally select one of the following additional states: CALC3:DRIF:DIFF:STAT (differenc
Programming Making Measurements The format of returned data Measurements are returned as strings All measurement values are returned from the Agilent 86120B 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 86120B 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 Byte register The Status Byte Register contains summary bits that monitor activity in the other status registers and queues. The Status Byte Register’s bits are set and cleared by the presence and absence of a summary bit from other registers or queues. Notice in the following figure that the bits in the Standard Event Status, OPERation status, and QUEStionable status registers are “or’d” to control a bit in the Status Byte Register.
Programming Monitoring the Instrument 4-18
Programming Monitoring the Instrument Table 4-3. Bits in Operation Status Register Bit Definition 0 not used 1 SETTling - indicating that the instrument is waiting for the motor to reach the proper position before beginning data acquisition. 2 RANGing - indicating the instrument is currently gain ranging. 3 not used 4 MEASuring - indicating that the instrument is making a measurement.
Programming Monitoring the Instrument Table 4-4. 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. 4 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 The *CLS common command clears all event registers and all queues except the output queue. If *CLS is sent immediately following a program message terminator, the output queue is also cleared. In addition, the request for the *OPC bit is also cleared. For example, suppose your application requires an interrupt whenever any type of error occurs. The error related bits in the Standard Event Status Register are bits 2 through 5.
Programming Monitoring the Instrument The error queue is first in, first out. If the error queue overflows, the last error in the queue is replaced with error -350, “Queue overflow”. Any time the queue overflows, the least recent errors remain in the queue, and the most recent error is discarded. The length of the instrument’s error queue is 30 (29 positions for the error messages, and 1 position for the “Queue overflow” message). The error queue is read with the SYSTEM:ERROR? query.
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 bytes (ASCII codes 49, 48, and 50). This 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.
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 1. Measure a DFB laser 4-30 Example 2. Measure WDM channels 4-32 Example 3. Measure WDM channel drift 4-34 Example 4. Measure WDM channel separation 4-37 Example 5. Measure SN ratio of WDM channels 4-39 Example 6. Increase a source’s wavelength accuracy 4-41 These programs are provided to give you examples of using Agilent 86120B remote programming commands in typical applications.
Programming Example Programs 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 86120B in the single-acquisition measurement mode. Then, it triggers the Agilent 86120B 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 4-31
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 86120B in the single-acquisition measurement mode. Then, it triggers the Agilent 86120B 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 Err_mngmt:SUB Err_mngmt COM /Instrument/ @Mwm DIM Err_msg$[255] INTEGER Cme CLEAR 7 REPEAT OUTPUT @Mwm; "*ESR?" ENTER @Mwm;Cme OUTPUT @Mwm; ":SYST:ERR?" ENTER @Mwm;Err_msg$ 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?"
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 86120B 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 86120B measures the drift on the laser.
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 Err_mngmt:SUB Err_mngmt(OPTIONAL Cmd_msg$) COM /Instrument/ @Mwmt DIM Err_msg$[255] INTEGER Cme CLEAR @Mwm REPEAT OUTPUT @Mwm;"*ESR?" ENTER @Mwm;Cme OUTPUT @Mwm;":SYST:ERR?" ENTER @Mwm;Err_msg$ IF NPAR>0 AND NOT POS(Err_msg$,"+0") THEN PRINT "This command ";Cmd_msg$;" makes the following error :" IF NOT POS(Err_msg$,"+0") THEN PRINT Err_msg$ UNTIL NOT BIT(Cme,2) AND NOT BIT(Cme,4) AND NOT BIT(Cme,5) AND POS(Err_msg$,"+0") Subend:SUBEND Set_ese:SUB Set_ese COM /Instrument/ @Mwm
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 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))/1.0E-9;" nm.
Programming Example Programs Example 5. Measure SN ratio of WDM channels 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 86120B to increase the absolute wavelength accuracy of Agilent 8167A, 8168B, and 8168C Tunable Laser Sources. Essentially, the Agilent 86120B’s accuracy is transferred to the tunable laser source. The absolute accuracy of the tunable laser source is increased from <±0.1 nm to <±0.005 nm which is the Agilent 86120B’s absolute accuracy (at 1550 nm).
Programming Example Programs COM Current_wl,Diff_wl.
Programming Lists of Commands Lists of Commands Table 4-7. Programming Commands (1 of 4) 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 4-7. Programming Commands (2 of 4) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. CALCulate1 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 4-7. Programming Commands (3 of 4) Command Description Codes: S indicates a standard SCPI command. I indicates an instrument specific command. :CALCulate3:DELTa:WPOWer[:STATe] Turns the delta wavelength and power measurement mode on and off. :CALCulate3:DRIFt:DIFFerence[:STATe] Sets the drift calculation to subtract the minimum values measured from the maximum values measured.
Programming Lists of Commands Table 4-7. Programming Commands (4 of 4) Command Description Code Codes: S indicates a standard SCPI command. I indicates an instrument specific command. HCOPy Subsystem :HCOPy:IMMediate Starts a printout. S Configures wavelength measurements for narrowband or broadband devices. Sets the elevation value used by the instrument to compensate for air dispersion. Sets the power offset value used by the instrument.
Programming Lists of Commands Table 4-8.
Programming Lists of Commands Table 4-8.
Programming Lists of Commands Table 4-8.
5 Common Commands 5-3 Measurement Instructions 5-15 CALCulate1 Subsystem 5-26 CALCulate2 Subsystem 5-31 CALCulate3 Subsystem 5-43 CONFigure Measurement Instruction 5-64 DISPlay Subsystem 5-64 FETCh Measurement Instruction 5-67 HCOPy Subsystem 5-68 MEASure Measurement Instruction 5-68 READ Measurement Instruction 5-69 SENSe Subsystem 5-69 STATus Subsystem 5-74 SYSTem Subsystem 5-79 TRIGger Subsystem 5-84 UNIT Subsystem 5-86 Programming Commands
Programming Commands Programming Commands Programming Commands This chapter is the reference for all Agilent 86120B programming commands. Commands are organized by subsystem. Table 5-1. 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 5-3.
Programming Commands Common Commands Example OUTPUT 720;”*ESR?” ENTER 720;Event PRINT Event *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.
Programming Commands Common Commands ensure all operations have completed before continuing the program. By following a command with an *OPC? query and an ENTER statement, the program will pause until the response (ASCII “1”) is returned by the instrument. Be sure the computer’s timeout limit is at least two seconds, since some of the Agilent 86120B commands take approximately one second to complete.
Programming Commands Common Commands *RST The *RST (reset) command returns the Agilent 86120B 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 5-4.
Programming Commands Common Commands Table 5-4. Conditions Set by *RST Reset (Continued) Item Setting Signal-to-Noise Measurements: measurement off wavelength reference auto reference (user) wavelength 1550 nm in vacuum number of averages (count) 100 GPIB address not affected Power-bar display on *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.
Programming Commands Common Commands The service request enable register is cleared when the instrument is turned on. The *RST and *CLS commands do not change the register. The *SRE? query returns the value of the service request enable register. Table 5-5. Service Request Enable Register Bita Bit Weight Enables 7 128 Not Used 6 64 Not Used 5 32 Event Status Bit (ESB) 4 16 Message Available (MAV) 3 8 Not Used 2 4 Error queue status 1 2 Not Used 0 1 Not Used a.
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[?] [SCALar]:LENGth :COHerence :ALPHa? :BETA? [:CLENgth]? :DELay? 5-16
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 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 Measurement Instructions MEASure[:SCALar]:LENGth:COHerence:BETA? Queries the beta constant. Syntax :LENGth:COHerence:BETA? Attribute Summary Query Only Description The beta constant is a unitless ratio. MEASure[:SCALar]:LENGth:COHerence[:CLENgth]? Queries the coherence length of the input signal in meters. Syntax :LENGth:COHerence:CLENgth? Attribute Summary Query Only MEASure[:SCALar]:LENGth:COHerence:DELay? Queries the round-trip path delay in the laser chip.
Programming Commands CALCulate1 Subsystem CALCulate1 Subsystem Use the CALCulate1 commands to query uncorrected frequency-spectrum data. In NORMAL measurement update mode, 34,123 values are returned. If the Agilent 86120B is set for FAST measurement update mode (low resolution), 4,268 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 in squared Watts (linear) units. No amplitude or frequency correction is applied to the values. To obtain the logarithmic (dB) result, normalize the returned values by the largest value, then take five times the logarithm of the returned values.
Programming Commands CALCulate1 Subsystem The frequency spacing between values is uniform and is equal to the reference laser frequency (473.6127 THz) divided by 64K, or 7.226756 GHz. Note the spacing between values is not uniform in wavelength units. The values returned are in ascending optical frequency. The first value of the uncorrected frequency data corresponds to an optical frequency of 181.6879 THz (1650.041 nm).
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 34123 or 4268. Other values result in an error.
Programming Commands CALCulate1 Subsystem Query Response For normal update: +34123 For fast update: +4268 5-30
Programming Commands CALCulate2 Subsystem CALCulate2 Subsystem Use the CALCulate2 commands to query corrected values frequency-spectrum 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 PEXCursion Sets the peak excursion limit used by the Agilent 86120B 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 POINts? Queries the number of points in the data set. Syntax :CALCulate2:POINts? Attribute Summary Preset State: unaffected *RST State: unaffected SCPI Compliance: instrument specific Query Only Description This is the number of points that will be returned by the CALC2:DATA? query. Query Response For example, if six laser lines are located: +6 PTHReshold Sets the peak threshold limit used by the instrument to determine valid laser line peaks.
Programming Commands CALCulate2 Subsystem Constant Value MINimum 0 dB MAXimum 40 dB 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.
Programming Commands CALCulate2 Subsystem Description When the state is on, the CALC2:DATA? POW query returns the total power and the CALC2:DATA? WAV, FREQ, or WNUM query returns the powerweighted average wavelength, frequency, or wave number values. Turning power-weighted average mode on while making delta, coherence length, or signal-to-noise measurements results in a “–221 Settings conflict” error. WLIMit[:STATe] Limits input wavelength range of the Agilent 86120B.
Programming Commands CALCulate2 Subsystem WLIMit:STARt:FREQuency Sets the starting 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 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 700.0 nm MAXimum wavelength limit stop value Attribute Summary Non-sequential command Preset State: 700 nm *RST State: 700 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 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 428.2750 THz Attribute Summary Non-sequential command Preset State: 249.8271 THz *RST State: 249.
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 14286 cm-1 (700 nm) Attribute Summary Non-sequential command Preset State: 8.333335E5 m-1 *RST State: 8.
Programming Commands CALCulate3 Subsystem CALCulate3 Subsystem Use the CALCulate3 commands to perform delta, drift, and signal-to-noise measurements.
Programming Commands CALCulate3 Subsystem ASNR:CLEar Clears the number of measurements used in the average signal-to-noise 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 signalto-noise calculation. The current measurement is used as the new reference for the average signal-to-noise 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 428.6 THz Attribute Summary Preset State: 428.6 THz (700 nm) *RST State:428.
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 700.0 nm MAXimum 1650.0 nm Attribute Summary Preset State: 700 nm (428.6 THz) *RST State: 700 nm (428.
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 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-tonoise 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 428.2750 THz Attribute Summary Preset State: unaffected by *RST State: 193.4145 THz (1550.0 nm in a vacuum).
Programming Commands CALCulate3 Subsystem SNR:REFerence[:WAVelength] Sets the wavelength used for the noise measurement reference in the signalto-noise calculation. Syntax :CALCulate3:SNR:REFerence[:WAVelength]{?| { | MINimum | MAXimum}} is a wavelength value that is within the following limits: Constant Description MINimum 700.0 nm MAXimum 1650.0 nm Attribute Summary Preset State: unaffected by *RST State: 1550.0 nm in a vacuum.
Programming Commands CALCulate3 Subsystem SNR:REFerence:WNUMber Sets the wave number used for the noise measurement reference in the signalto-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 14286 cm-1 (700 nm) Attribute Summary Preset State: unaffected by *RST State: 6451.
Programming Commands CONFigure Measurement Instruction 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. Refer to “Measure delta, drift, and signal-to-noise” on page 4-14 for additional information on selecting measurements. CONFigure Measurement Instruction For information on the CONFigure measurement instruction, refer to “Measurement Instructions” on page 5-15.
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 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. MARKer:MAXimum:PREVious Moves the marker to the laser line that has the next higher power level.
Programming Commands FETCh Measurement Instruction Description Moves the marker from the current marker position to the next laser line having the following characteristic: • longer wavelength • higher frequency • higher wave number If the display is in the List by Ampl mode, it will be changed to List by WL before the marker is moved. [WINDow]:GRAPhics:STATe Turns on and off the display of the power bars.
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 86120B’s rear-panel PARALLEL PRINTER PORT connector.
Programming Commands READ Measurement Instruction READ Measurement Instruction For information on the READ measurement instruction, refer to “Measurement Instructions” on page 5-15. 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. This command applies to Agilent 86120B instruments with firmware version number 2.0. When first turned on, the instrument briefly displays the firmware version. Instruments with a firmware version number less than 2.0 do not have this feature.
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 86120B 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 Query Response The query form returns the current offset setting as shown in the following example: +5.00000000E+000 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.
Programming Commands STATus 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+000,+1.5 3320300E+000,+1.50097700E+000,+1.47265600E+000,+1.50293000E+000,+1.50781300E+000,+1.51171 900E+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 {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 4-16.
Programming Commands STATus Subsystem Query Response When queried, the largest value that can be returned is 65535. This is because the most-significant register bit cannot be set true. {OPERation | QUEStionable}[:EVENt] Queries the contents of the questionable or operation event registers.
Programming Commands STATus Subsystem Description Changes in the state of a condition register bit causes the associated OPERation Status or QUEStionable Status register bit to be set. This command allows you to select a negative bit transition to trigger an event to be recognized. A negative transition is defined to occur whenever the selected bit changes states from a 1 to a 0. You can enter any value from 0 to 65535. When queried, the largest value that can be returned is 32767.
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 5-7.
Programming Commands SYSTem Subsystem SYSTem Subsystem The commands in this subsystem have the following command hierarchy: :SYSTem :ERRor? :HELP :HEADers? :PRESet :VERSion? 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 86120B has a 30 entry error queue. The queue is a first-in, firstout buffer.
Programming Commands SYSTem Subsystem Example DIM Error$[250] OUTPUT 720;”:SYSTEM:ERROR?” ENTER 720;Error$ PRINT Error$ HELP:HEADers? Queries a listing of all the remote programming commands available for the Agilent 86120B. 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 arbitrary-block data format.
Programming Commands SYSTem Subsystem *SRE *STB?/qonly/ *TRG/nquery/ *TST?/qonly/ *WAI/nquery/ 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 5-8.
Programming Commands SYSTem Subsystem Table 5-8.
Programming Commands SYSTem Subsystem VERSion Queries the version of SCPI that the Agilent 86120B 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 86120B is 1995.0. Table 5-9. 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 86120B has no ARM or TRIGger commands. The commands in this subsystem have the following command hierarchy: ABORt INITiate :CONTinuous [:IMMediate] ABORt Halts the current measurement sequence and places the instrument in the idle state.
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 UNIT 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 86120B to wait for non-sequential commands” on page 4-12 for more information.
6 Test 1. Absolute Wavelength Accuracy 6-3 Test 2. Sensitivity 6-4 Test 3. Polarization Dependence 6-5 Test 4. Optical Input Return Loss 6-6 Test 5.
Performance Tests Performance Tests Performance Tests The procedures in this chapter test the Agilent 86120B’s performance using the specifications listed in Chapter 7, “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 1. Absolute Wavelength Accuracy Test 2. Sensitivity Test 3. Polarization Dependence Test 4. Optical Input Return Loss Test 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 86120B’s input circuitry can be damaged when total input power exceeds 18 dBm. Procedure Use three or four light standards that cover the Agilent 86120B’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 86120B’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 86120B’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 Model Procedure: Standard instruments (flat contacting connectors) 1 Turn the source module’s output off.
Performance Tests Test 4. Optical Input Return Loss 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 DUT 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 Amplitude linearity is performed using the following devices: Equipment • • • • 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 After completing this step, the first two columns of the table should be completely filled in. 10 Disconnect the fiber-optic cable from the optical power meter and connect it to the Agilent 86120B’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 86120B’s front-panel Preset key.
Performance Tests Test 5. Amplitude Accuracy and Linearity amplitude plateaus separated by small amplitude steps. This is not a problem as long as the amplitude steps are within the linearity specification. Table 6-1.
7 Definition of Terms 7-3 Specifications 7-6 Regulatory Information 7-10 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. Four He-Ne gas lasers are used.
Specifications and Regulatory Information Definition of Terms Amplitude Calibration Accuracy indicates the maximum power calibration error at the specified wavelengths over the allowed environmental conditions. The amplitude calibration accuracy is traceable to a National Institute of Standards and Technology (NIST) calibrated optical power meter. NIST is the national standards laboratory of the United States.
Specifications and Regulatory Information Definition of Terms Measurement Cycle Time Measurement cycle time refers to the cycle time when measuring wavelength and power of laser lines. Specific advanced applications may require longer cycle times.
Specifications and Regulatory Information Specifications Specifications 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: • NORMAL update mode unless noted. Refer to “Measurement rate” on page 2-14. • Configured to measure narrowband devices. Specifications do not apply when the instrument is configured to measure broadband devices.
Specifications and Regulatory Information Specifications Amplitude Calibration accuracy at calibration wavelengths ±30 nm 1310 and 1550 nm ±0.5 dB 780 nm (characteristic) ±0.5 dB Flatness, ±30 nm from any wavelength 1200-1600 nm (characteristic) ±0.2 dB 700-1650 nm (characteristic) ±0.5 dB Linearity, 1200 nm to 1600 nm, lines above –30 dBm ±0.3 dB Polarization dependence 1200-1600 nm ±0.5 dB 700-1650 nm (characteristic) ±1.0 dB Display resolution 0.
Specifications and Regulatory Information Specifications Selectivity Two lines input separated by ≥100 GHz (characteristic) 25 dB (characteristic) Two lines input separated by ≥30 GHz (characteristic) 10 dB (characteristic) Input Power Maximum displayed level (sum of all lines) +10 dBm Maximum safe input level (sum of all lines) +18 dBm Maximum Number of Laser Lines Input 100 Input Return Loss With flat contacting connectors 35 dB With angled contacting connectors (Option 022) 50 dB Measureme
Specifications and Regulatory Information Specifications Operating Specifications Use indoor Power: 115 VAC: 110 VA MAX. / 60 WATTS MAX. / 1.1 A MAX. 230 VAC: 150 VA MAX. / 70 WATTS MAX. / 0.6 A MAX.
Specifications and Regulatory Information Regulatory Information Regulatory Information • Laser Classification: This product contains an FDA Laser Class I (IEC Laser Class 1) laser. • This product complies with 21 CFR 1040.10 and 1040.11. Notice for Germany: Noise Declaration Acoustic Noise Emission Geraeuschemission LpA < 70 dB LpA < 70 dB Operator position am Arbeitsplatz Normal position normaler Betrieb per ISO 7779 nach DIN 45635 t.
Specifications and Regulatory Information Regulatory Information Declaration of Conformity 7-11
Specifications and Regulatory Information Regulatory Information Front view of instrument Rear view of instrument 7-12
8 Instrument Preset Conditions 8-2 Menu Maps 8-4 Error Messages 8-9 Front-Panel Fiber-Optic Adapters 8-15 Power Cords 8-16 Agilent Technologies Service Offices 8-18 Reference
Reference Reference Reference Instrument Preset Conditions Table 8-1.
Reference Instrument Preset Conditions Table 8-1.
Reference Menu Maps Menu Maps This section provides menu maps for the Agilent 86120B 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 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 Delta On Menu Delta Off Menu 8-6
Reference Menu Maps Display Peak WL and System Preset Menus Measurement Single Menu There is no menu associated with this key.
Reference Menu Maps System Setup Menu 8-8
Reference Error Messages Error Messages In this section, you’ll find all the error messages that the Agilent 86120B can display on its screen. Table 8-2 on page 8-9 lists all instrument-specific errors. Table 8-3 on page 8-12 lists general SCPI errors. Table 8-2.
Reference Error Messages Table 8-2.
Reference Error Messages Table 8-2.
Reference Error Messages Table 8-3.
Reference Error Messages Table 8-3. 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 8-3. General SCPI Error Messages (3 of 3) Error Number 8-14 Description –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.
Reference Power Cords Plug Type Cable Part No. Plug Description Length (in/cm) Color Country 250V 8120-4211 Straight SABS164 79/200 Jade Gray 8120-4600 90° 79/200 Republic of South Africa India 100V 8120-4753 Straight MITI 90/230 8120-4754 90° 90/230 Dark Gray Japan * Part number shown for plug is the industry identifier for the plug only. Number shown for cable is the Agilent Technologies part number for the complete cable including the plug.
Reference Agilent Technologies Service Offices Agilent Technologies Service Offices Before returning an instrument for service, call the Agilent Technologies Instrument Support Center at (800) 403-0801, visit the Test and Measurement Web Sites by Country page at http://www.tm.agilent.com/tmo/country/English/ index.html, or call one of the numbers listed below. Agilent Technologies Service Numbers Austria 01/25125-7171 Belgium 32-2-778.37.
Index Numerics 1 nm annotation, 3-5, 3-8 A ABORt programming command, 5-84 ABORT softkey, 2-29 ac power cables, 1-7 adapters fiber optic, 8-15 adding parameters, 4-25 address.
Index adapters, 1-22 cabinet, vii, 1-2 fiber-optic connections, 1-13, 1-21 non-lensed connectors, 1-21 CLEAR softkey, 3-10 CLENgth? programming command, 5-25 *CLS, 4-21, 5-3 CM –1 softkey, 2-14 Cmd_opc subroutine, 4-29 COH LEN softkey, 3-12 coherence length, iii, 3-12, 7-8 colon, 4-25 commands combining, 4-24 common, 4-23 measurement instructions, 4-23 non sequential, 4-12, 5-29, 5-33, 5-35, 5-36, 5-37, 5-38, 5-39, 5-40, 5-41, 5-42, 5-71, 5-85, 5-86 standard SCPI, 4-23 termination, 4-27 common commands *CL
Index ENABle programming command, 5-75 EOI signal, 4-27 Err_mngmt subroutine, 4-29 error messages, 8-9 queue, 4-21 ERRor programming command, 5-79 Error_msg subroutine, 4-28 *ESE, 4-28, 5-3 *ESR, 5-5 EVENT programming command, 5-75, 5-76 event status enable register, 4-28, 5-4 example programs, 4-28 increase source accuracy, 4-41 measure DFB laser, 4-30 measure SN ratio, 4-39 measure WDM channel drift, 4-34 measure WDM channel separation, 4-37 measure WDM channels, 4-32 external attenuation, 2-25 extra, 1
Index aperture, vi, 1-9 classification, vi, 7-9 drift, iii, 3-9, 3-10 line separation, iii, 2-20 linewidth, 2-2 modulated, 2-23 tuning power, 2-4 LEFT programming command, 5-65 LIM OFF softkey, 1-12, 2-8 LIM ON softkey, 1-12, 2-8 LINE key, 1-8 linearity, 7-4, 7-7 line-power cable, 1-6 cables, 8-16 initial state, 5-81, 8-2 input connector, 1-5 requirements, 1-6 specifications, 7-9 linewidth, 2-2 List by Power menu map, 8-5 mode, 4-9 softkey, 2-7, 3-10 List by WL key, 2-6 menu map, 8-5 mode, 4-9 softkey, 2-6
Index new-line character, 4-27 NEXT PK softkey, 2-5 NEXT programming command, 5-65 NEXT WL softkey, 2-5 NM softkey, 2-14 noise declaration, 7-10 noise power automatic interpolation, 3-4 bandwidth, 3-5, 3-8 user entered wavelength, 3-5 non-sequential command, 4-12, 5-29, 5-33, 5-35, 5-36, 5-37, 5-38, 5-39, 5-40, 5-41, 5-42, 5-71, 5-85, 5-86 NORMAL softkey, 2-14, 4-9, 5-73 notation definitions, 5-2 NTRansition programming command, 5-76 NUM LINES < NUM REFS, 3-10 NUM LINES > NUM REFS, 3-10 numbers, 4-25 O Of
Index PWR OFS annotation, 2-25 softkey, 2-25 ∆ PWR softkey, 2-22 Q queries, 4-27 multiple, 4-27 queues, 4-21 R radiation exposure, vi, 1-9 range, wavelength, 4-4, 5-36 range, wavelengths, 2-8 READ measurement instruction, 5-15 rear panel labels, 7-12 regulatory duration, 7-2 Remote annotation, 4-3 repetitive data formats, 3-5 RESet programming command, 5-56 RESET softkey, 2-22, 3-9, 3-11 return loss, 7-4, 7-8 returning data, 4-27 returning for service, 1-23 RF modulation, 2-24 RIGHT programming command,
Index *STB, 5-12 STD AIR annotation, 2-26 softkey, 1-11, 2-27 subsystems, 4-23 swabs, 1-20 syntax rules, 4-23–4-27 SYSTem subsystem, 5-79 T Tempo subroutine, 4-29 terahertz, 2-14 THRSHLD softkey, 2-19 THZ softkey, 2-14 total power, iii, 2-7 maximum measurable, 2-25 measuring, 2-7 transient data, 4-10 *TRG, 5-13 trigger ignore, 8-13 TRIGger subsystem, 5-84 *TST, 5-13 wavelength definition of, 7-3 input range, 2-2 peak, 2-4 range, 2-8, 4-4, 5-36 separation, 2-20 specifications, 7-6 WAVelength programming c
