[time-nuts] 10 MHz over optical fiber?

[Paul Boven]

Hi Didier, everyone,

Didier wrote:
> By the time you get the signal from the maser through 34 km of fiber optic,
> what you get at the end might be not better than a decent GPSDO...

That's exactly what I'm trying to work out before I'll actually start
building something like that. The JPL device (thanks for the hint, James
P. Lux) is very interesting, see:
http://tycho.usno.navy.mil/ptti/1988/Vol%2020_02.pdf

The JPL system aims to achieve better than 1E17 in 1000s, whereas the
H-maser in their publication is quoted as 1E15 in the same averaging
time. They also state that: 'when stabilities higher than 1E15 are
required the link must be actively stabilized'. So, in a nutshell - If I
were to build such a system, the first incarnation would be without such
a compensation system.
If such a compensation does turn out to be necessary I'd probably not
use a 50% mirror but simply loop the received data back to the
trasmitter of the SFP at the receiving end, and use a fiber pair instead
of a single fiber.

Regards, Paul Boven.