Drift Measurement - Viavi 8100 V2 Series User Manual

Drift measurement

The OSA-xxx modules provide a Drift measurement application to perform multiple
measurements and display the recorded results in a graphical format (trace) over the
time.
This can be used to monitor the drift of power, wavelength and SNR of optical systems
or components. This is important to measure the drift of non temperature stabilized
transmitter in CWDM networks.
NOTE
A Drift measurement can only be done at predefined wavelengths or fre-
quencies, for this reason a reference Grid needs to be defined and the
Channel Detection parameter is set to Grid.
The following parameters need to be set for Drift measurements:
Number of Sweeps
Interval
NOTE
Interval specifies the time between start of one measurement and start of the
next measurement and includes the instrument measurement time
All channels defined by the channel Grid can be monitored simultaneously with the drift
application. To show the monitored measurement parameter use the Trace/Channel/
Drift button in the result screen.
This button has a toggle function with the following selections:
• Trace: in Trace mode the up/down cursor change the active trace in a multiple
trace display
• Channel: in Channel mode the up/down cursor changes the channel to be
displayed over time.
• Drift: activates the drift display showing the selected parameter over time
Activating the Drift display will show the following screen:
Defines the number of sweeps (1 to 10.000)
Defines the time between the measurements. Similar to Wait
Period of Long Term application (see
page 252).
User Manual
Chapter 8 Optical Spectrum Measurement
78000010220 Rev. 024
Drift measurement
"Wait Period" on
277