On Tue, 9 Jul 2002, Brendan Moran wrote:

>> Of course the golden mile is important, especially if you can DIY and if
>> you can skip the backbone altogether ;-). Look for a DIY point to point
>> 10MBps optical link from Czechia called metropolis. URL:
>>
>
>err... I had thought that several GBps was in a little bit of a different
>class.  Anyways, anyone know how high a datarate you can get out of the LED
>in a laser pointer?

In theory, about c/(2*lambda) Hz (== Bauds in this case). In practice, as
much as you can drive the device to. Diodes for high data rates have
special design (like controlled impedance feeds and such). I once had a
book that showed how to interface a laser diode to a ham RF transmitter
for 432MHz. It consisted of an impedance matching network and a fast diode
or two, plus a very simple bias network that used a D cell I think. The Tx
ran 10-20W into the air cooled diode.

Peter

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