EXFO IQS-1600 High-Speed Power Meter for IQS-500/600 - Manual (Page 108)

Typical Applications
100 IQS-1600
Characterizing an Optical Switch
6. At this time, both the attenuator and power meter will display “0.0 dB”.
Increase the attenuation using constant step sizes, while recording the
values from both displays (attenuator and power meter) at each step.
Continue until the power meter indicates around −55 dB. The recorded
values at each step should follow within allowable tolerances of both
instruments. If the values do not correspond, this indicates a problem
with the equipment setup or with one of the instruments. Before
proceeding any further, the problem must be isolated.
To test the linearity of an optical detector:
1. Switch off the source.
2. Disconnect the high-speed power meter from the circuit shown in the
previous page and replace it with the detector being tested.
3. Reset the attenuator to minimum attenuation.
4. Switch on the source and allow it to stabilize (the recommended time
is 20 minutes).
5. Increase the attenuation on the attenuator with constant step sizes,
while recording the output read by the detector at each step.
6. When completed, the data can be analyzed to determine the
detector’s linearity.
Characterizing an Optical Switch
The high sampling rate, fast stabilization and trigger capability of your
high-speed power meter can be combined to easily characterize
optical switches.
The figure on the following page displays a simple test station for a 1 x 2
optical switch. A light source is connected to the common terminal of the
optical switch. Each optical output of the switch is connected to a
dual-channel power meter detector. This setup can be used to test both the
repeatability and the settling time of the optical switch. For the latter test (in
Single acquisition mode), the electrical signal used to command the
switch is also connected to the external trigger input of the power meter.