[Laser] Thoughts on receiver design

[Art]

Hi Phil and group members.

I have long been interested in the PGP front end. It's very cheap to build 
and should be low noise as long as it's shielded well.

I have modeled the PGP detector in Spice. I cannot find a spice model for a 
photodiode, so I used a pin diode without a current source. In this mode, 
only the dc operating points can be determined.

Both transistors appear to operate fine and it does indeed convert small 
input currents into voltage.

I can't proceed further without a good photodiode spice model.

I have my doubts regarding it's usefulness for daylight laser reception as 
there is no active sensor to detect ambient light and to change the bias 
point with varying ambient light levels.

Good luck to all.

Art





>If I go the route of the K3PGP design what is the best
>PIN diode sensor to choose? I have been looking into
>the Photonics Detectors PDB-V107 as a possibility.
>What are other people using with the 'PGP front end
>design?