[time-nuts] Photodiodes for high frequency OPLL

David Kirkby david.kirkby at onetel.net
Sun Mar 31 10:27:02 EDT 2013

On 31 March 2013 13:52, Attila Kinali <attila at kinali.ch> wrote:
> But probably using an APD with gain modulation at 1GHz or so, i could
> down modulate the signal to something that is easier to handle
> (ie something similar as a direct conversion software defined radios).
> I wonder if this would work with normal PIN photodiodes as well, as
> their price is much lower than APDs.
>                         Attila Kinali

You can't modulate the sensitivity of a PIN diode by an adjustable
bias like you can in an APD. For a PIN diode, at the wavelengths you
are talking of, you basically get around 0.5 Amps/Watt from the diode.

APDs are not that expensive, especially the small ones you will need
for this. But I still can't really see a solution - I was just
clutching at straws.


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