Keysight Technologies N778 C Series Programming Manual page 90

5 Polarization Commands
Command: :STABilizer:SOP
Syntax: :STABilizer:SOP<wsp> <s1>,<s2>,<s3>[,<Factor>]
Description: Sets the target SOP for the Stabilizer.
•
•
•
Parameters: None
Response: None
Example: N7786C/88C: → stab:sop 0,1,0
N7785C: → stab:sop 0,0,0,1.234
Affects N7785C, N7786C, N7788C
Command: :STABilizer:SOP?
Syntax: :STABilizer:SOP?
Description: Gets the target SOP.
NOTE - For the N7786C/88C, when the Stabilizer invert is On, then the STABilizer:SOP? command returns the inverted
Target SOP which is the SOP the Stabilizer uses.
Parameters: None
Response: A 4-element Stokes vector.
Example: N7786C/88C: stab:sop? → +0.00000000E+00,+1.00000000E+00,+0.00000000E+00
N7785C: stab:sop? → +0.00000000E+00,+0.00000000E+00,+0.00000000E+00,+1.23400000E+00
Affects N7785C, N7786C, N7788C
90
For the N7786C and N7788C which have a build in Polarimeter the target SOP must be provided as a 3-element
normalized Stokes vector (s1,s1,s3 with DOP=1). If the DOP is not 1, then it will be normalized before processing.
For stabilizing with the N7785C, the fourth parameter must be used. The first 3 parameters should be '0' and the
feedback parameter <Factor> is a positive real number. Periodic repetition of this command with updated Factor values,
each followed with the command 'TRIG 1' will adjust the polarization to minimize <Factor>.
The procedure for stabilizing with the N7785C is:
STABilizer:STABilize 0 To deactivate stabilization
STABilizer:STABilize 1 To activate stabilization
STABILIZER:SOP 0,0,0,A To enter the feedback parameter A
TRIG 1To trigger the next stabilization dithering step
The last 2 steps should be repeated with updated values. Repetition rates of 10 to 20 Hz are fine. The stabilizer will work
to minimize the parameter A, which should be a positive real number. The feedback parameter can be scaled to improve
the convergence rate. Maximum values between 1 and 100 are reasonable.
Keysight N778xC Series Polarization Instruments Programming Guide