GPIB communication with HP 8509B and an HP8163A/81689A tunable laser?

[ucsd student]

I am trying to measure polarization and obtain Stokes parameters using the HP 8509B polarization analyzer and an HP 8163A multimeter mainframe with an HP 81689A tunable laser.  I am using GPIB and MATLAB to communicate with the two instruments.  The HP 8509B measures polarization of 1) its own internal laser, 2) an external laser which it can control but only HP8167A/HP8168A  3) or a manually tuned laser. 

I am trying to obtain polarization measurements using a manually tuned external laser but when queried for what source it is reading the polarization analyzer returns "manually tuned, off" even when the laser is on and the Poincare sphere shows a signal.  A query of "stokes?" returns "FAIL".

If anyone has tried to control the HP 8509 and a tunable laser other than an HP8167A/8168A and has encountered this problem I would sure appreciate some advice on how to proceed.

THANKS!!!

[JohnM 64]

Hello,

I want to first ensure that you are able to use the GPIB equipment without any error.  Do you obtain any error messages when sending and receiving from these instruments, or are you just receiving data that you do not expect to receive?

I have not used any of the HP equipment, but perhaps someone else in the forums has... or this may be a case when it would be helpful to call HP for help with their specific instruments.  Anyone else have any ideas?

Have a great day!

john m
Applications Engineer

[ucsd student]

I have successful communication to activate the laser and to adjust the power and wavelengths. 

I have found that even though I can modify the power level to what I specify, when I query the laser for its output power it always returns the same thing 4.1 mW instead of the 10 or 15 mW that the display reads out.  The wavelength can be controlled by commands and also returns the correct numbers when queried.

The polarization analyzer is responsive when the internal laser is being used but not when the internal is turned off and the external is activated.  I have made sure the internal shutter is off.  The signal appears on the poincare sphere but the data values being displayed are not retrievable. 

I will keep trying and call in for help soon if I do not figure it out.

thanks.