I am not sure this is correct. In-line optical amplifiers work by stimulated emission like a laser rod. There is no intermediate electronic stage. The amplifier is a section of fibre that is doped with a rare earth element. The rare earth atoms are boosted into a

high energy state using a power source around the fibre. Passing signals (photons) stimulate the decays of the metastable states releasing more photons and boosting the signal. I am not sure what the effect of this on

metastable the

polarisation characteristics of the signal is but my *hunch* is that the polarisation characteristics would be preserved in the amplified signal.

Sherry

ps Any laser physicists in the house?

Dr. Simon Phoenix (my resident quantum crypto guru) says no, you can't use em - you have to build secure repeaters. Simon has been doing this sort of thing in the Lab for years. He's simon@alien.bt.co.uk if you want to probe him gently. /.J BTW: You can build an Erbium doped amp that is 'transparent' to your secure channel.