Filter
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Using the Instrument
Analyzer Operating Modes
Accessing the filter mode (for 86144B/86146B only)
Note Filter mode will not function in zero span. The filter mode selection will be
shaded out. The current state before entering filter mode will not be saved. A
sweep will not be taken. The reference level will not change.
1 Connect the light source to the optical spectrum analyzer’s front panel
monochromator input connector.
2 Connect the monochromator output to the photodetector input.
3 Press Appl’s > Measurement Modes > Filter Mode. Follow the external
path align setup instructions and select either the Switch Path Auto Align Now
or Switch Path No Auto Align.
• Select the Switch Path Auto Align Now to perform an automatic align-
ment of the external path.
• Select Switch Path No Auto Align if you do not have the monochromator
output connected to the photodiode input, or to preserve previous align da-
ta.
Switch Path Auto Align Now switches to the 9
µm filter mode path and
performs an Auto Align. This aligns the output of the monochromator with the
photodetector input for improved amplitude accuracy. The automatic align-
ment procedure should be performed whenever the instrument has been:
• moved
• subjected to large temperature changes
• turned off, then on, and warmed up for an hour
The automatic alignment requires the connection of an external light source.
This can be a broadband or narrowband source. If there is insufficient signal
power, the automatic alignment will not be performed and an error message
will be reported.
The Auto Align function saves and restores the current instrument state. This
allows the auto align to be used in the middle of a measurement routine.
If markers are turned on, auto align attempts to do the automatic alignment at
the wavelength of the active marker.
Note Auto Align Now will overwrite any previous align data.