The circuit I've seen is: |--||------------------- +Vb-------o--|<--------------------> amp |--||-o----------------- Vb gnd----------|
The diode is reverse biased by 50 to several hundred volts. The two caps are DC bypass caps w/ very short leads. The output is a 50 Ohm coax to a broadband amp w/ 50 Ohm input. In the limit, the amp is put right at the detector and has near-zero input Z. Best, -John ================= > On Sat, 30 Mar 2013 10:52:54 -0700 (PDT) > "J. Forster" <j...@quikus.com> wrote: > >> My understanding is that you want to operate photodiodes with high >> reverse >> bias for the best frequency response. The bias widens the space charge >> layer, thereby reducing the capacitance of the device. The high electric >> fields in the SCL region also sweeps the hole-electron pairs, produced >> by >> photon injection, out faster, hence improving the response as well. Such >> devices are best operated with very low capacity wiring into a virtual >> ground. > > Could you elaborate on this circuit a little bit? > Some terms i could google for or pointers to books/papers to read? > > >> Of course, there are limits as, at some point, the device will >> avalanche. >> When that ocurrs, the device will have gain akin to a photomultiplier. >> >> Some devices are actually designed to operate in this mode, but, since >> the >> thing is so near to unstable requires careful control of temperature and >> oher parameters. > > Yes, the avalanche photodiodes are meant for this operation. > Yes, there are kind of sensitive. But i think that's managable. > > Attila Kinali > > -- > The people on 4chan are like brilliant psychologists > who also happen to be insane and gross. > -- unknown > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.