PMD Compromise
All,
I don't have a vested interest as ether a component vendor or as a system vendor. Please let me propose the following compromise
for PMDs:
2 single mode PMDs;
1300nm, 12db for 10km over SM,
1300nm, 20db for 40km over SM,
2 multi-mode PMDs;
850nm, serial, for 100m over MM
850nm, WWDM, for 300m over MM
I have changed my stance on the SM solution because several of my colleges in the telephony industry are miss-interpreting the
1500nm proposal as an indicator that tight tolerance lasers will be part of the standard. The best way to "kill" that is to not
have a 1500nm solution.
The 12db 1300nm PMD will have adequate power to support transparent optical cross connects in an intra-facility installation as well
as metro fiber that has a lot of splices. The 20db 1300nm PMD will have adequate power to support 40km over the same metro fiber
that has the high number of splices. Both will also be able to support quite a few fiber patch panels, which can occur in some
"riser" situations. The 12db 1300nm PMD can be used in shorter intra-facilities installations with the use of in-line attenuators,
which is common in carrier facilities today.
The 850nm serial and WWDM solutions provide for MM fiber which is preferable in intra-server and intra-router interconnect within a
computer room. They will also support a certain amount of MM facilities fiber installations.
I don't know if this helps or just adds fuel to the flames, but I hope that this will help make progress within the TF.
Thank you,
Roy Bynum