Setting Up and Executing a Scan
Scanning the Poincare Sphere
Agilent
8169A
Polarization Controller, Second Edition
31
Setting Up and Executing a Scan
The sphere application changes the state of polarization over time, by
rotating the
λ
/2 and
λ
/4 plates. The rotations can be done slowly, to give a quasi-
randomly polarized signal, which you can use, with suitable data logging to
measure polarization dependence. The rotations can be done quickly, to give a
quasi-depolarized signal, which you can use, with suitable measurement
averaging time to measure depolarized response.
1
Press
to select the application.
2 Set the speed at which the
λ
plates rotate:
• Set Speed to Fast and the averaging time of your power meter to longer than 1s
to get measure the response to depolarized signal. If it is not already selected:
a
Move the Modify knob.
b
Select Fast using the Modify knob
or
.
c
Press
or
.
• Set Speed to Slow and the averaging time of your power meter as short as pos-
sible, and use logging to measure polarization dependence. If it is not already
selected:
d
Move the Modify knob.
e
Select Slow using the Modify knob
or
.
f
Press
or
.
3
When everything is setup, press
to start the scan.
During the scan, values for the angle of
λ
/4 and
λ
/2 are shown on the display.
These values are samples. The
λ
plates rotate continuously.
The Pol filter angle shown here is the same as the one shown when you
press
. If you have already set this value, there is no need to change
it.
N O T E