[time-nuts] sub cables
bruce.griffiths at xtra.co.nz
Thu May 1 18:47:03 EDT 2008
Magnus Danielson wrote:
> From: Scott Mace <smace at intt.net>
> Subject: Re: [time-nuts] sub cables
> Date: Thu, 01 May 2008 16:30:43 -0500
> Message-ID: <481A3683.4050300 at intt.net>
>> A repeater or regen goes optical-electrical-optical. I think you are
>> talking about an EDFA. While it may pass light when it's down, one
>> has to take into account the optical budget of the span.
> Modern sub cables does not used a distributed line of EDFAs anymore. They use
> the entire cable length as an amplifier instead. If the laser is down, you can
> reach it and service it, since it sits on dry land anyways.
> I have an EDFA lying around my office desk. Never know when I need one.
> Uses a 250 mW 850 nm pumping laser.
There is a limit to the cable length when using EDFAs above which a
regenerator is required.
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