User`s guide

FILTer: Channel subcommand that sets the filter for the specified channel or reads the current setting. Valid filter
settings depend upon the type of channel that is installed in the OE-2. Valid settings can be determined from
the TYPE field of the INStalled query. Example read: ‘:CHAN1:FILT?’.
INStalled: Channel subcommand that provides a query response only. When queried the command returns a comma
delimited field with information pertaining to the specified channel. The fields returned are channel type (or
option), current filter setting, current amplifier setting, current wavelength setting, OE-2 Channel Status
(Single/Dual), and OE-2 release (B01.00 – Beta 1.00, R01.00 Production 1.00). Example read: ‘:CHAN1:INS?’.
NULLoffset: Channel subcommand that sets or reads the null offset of the specified channel. The null offset value
is computed from a calibration that is performed when the specified channel’s optical input is dark. The null
offset is then used to compensate the power monitor for this ‘null’ condition. When performing a null offset
calibration, the null offset must first be written to zero. Example write: ‘:CHAN1:NULL 0’.
TYPE: Channel subcommand that provides a query response only. The type (or option) of the OE-2 channel is
returned in a ‘/’ delimited field. The return string contains the filter positions that are available for the specified
channel. Valid strings are given in the chart above. Example read: ‘:CHAN1:TYPE?’.
WAVElength: Channel subcommand that set the wavelength for the specified channel or reads the current setting.
The wavelength setting determines the calibration constant that is used in the average power measurement. Any
wavelength setting that does not match the input optical wavelength will result in an incorrect average power
reading. Wavelength units are meters. Example write: ‘:CHAN1:WAVE 1550E-9’.
SYSTEM: Root command for system wide commands.
ADFormat: System subcommand that sets or reads the current A/D format. The A/D format specifies the way
results are returned. When set to BITS the AVEP command returns the bit reading from the A/D Converter in
the power monitor. When set to WATTS the AVEP command converts the A/D voltage into a power reading.
The BITS mode is used during a null offset calibration.
CALIBRATE: Root command for calibration commands.
CALType: Calibrate subcommand that sets or reads the current calibration type. A short calibration does not
require any external readings but may be less accurate than a long cal. During a long cal the ADFormat is set to
BITS and readings are taken with the AVEPwr command. The readings can be averaged over several seconds
to improve the accuracy of the calibration. The averaged value (in BITS) is then written using the NULLoffset
command. Example Cal sequence:
Short Cal:
:CAL:CALT SHORT
:CHAN1:NULL
Long Cal:
:CAL:CALT LONG (set long cal mode)
:SYSTEM:ADFORMAT BITS (set format to BITS)
:CHAN1:NULL 0 (Zero out the current null)
:CHAN1:AVEP? (Read this multiple times over a period of several seconds and average the results)
:CHAN1:NULL <AVERAGED DATA> (write the averaged data)
:SYSTEM:ADFORMAT WATTS (return format to WATTS)
| APPENDIX B | GPIB Commands
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