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I am trying to understand fiber optic communication over long distances:

Can optical fibre communication links be used for a length of 100km as well as 100000km without having to change sender and receiver equipment? What are physical limitations besides the typical loss of 0.2 dB/km?

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What kind of link would you need that is 100000km? That would be a fiber that goes around the earth at the equator 2.5 times. But it is 1/4th the distance to the moon. – Zoredache Nov 21 '11 at 18:32
@Zoredache Tethered suborbital frikkin' lasers – voretaq7♦ Nov 22 '11 at 18:33
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Can optical fibre communication links be used for a length of 100km as well as 100000km without having to change sender and receiver equipment?

In short, no. Any fiber run of decent length is going to require specialized high-power laser optics on both ends as well as some sort of in-line amplification. These days, EDFAs are typically used on very long-haul runs.

To clarify, short-haul runs and long-haul runs need different optics. If you tried to use short-haul optics on too long of a run, there will be too much attenuation and you'll never get link. Theoretically you could use long-haul optics on a shorter circuit, however you'd need optical attenuators on each end so you don't blow out the receivers.

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