On Wednesday, February 27, 2013 4:02:19 PM UTC, Tim Streater wrote:
In article ,

wrote:

It's a long while since I was using LEDs to drive optical fibre links, but I
recall that they ran out of steam at around 10MHz for most types, with some
specialized ones managing up to 100MHz. Almost all the links I've looked at
since (and everything at above 100 Mbit/s) use lasers, and a high proportion
of those use a separate (even if possibly integrated in the same package)
modulator.

I have this recollection that the short range optic modules for Juniper
routers (over multi-mode fibre) used IR LEDs at 850 nm. These would be
driven at any speed up to 10Gbps. The longer range modules (up to 60km
or so of single-mode fibre) were all lasers at 1310 or 1550 nm.

Are you sure they were LEDs? I'd have expected them to be VCSELs (vertical cavity surface emitting lasers); I've seen a lot of gigabit ethernet modules for short distances that use 850nm VCSELs.
Mike