On Mon, 1 Oct 2012, tom@ninjabadger.net wrote:
If you can afford Wave Logic 3 interfaces for your Nortel^WCiena 6500's, you'll find some pretty impressive things are actually possible, including 100G per 100GHz guide over very large distances (think Atlantic-large).
The amount of processing power and equipment in the transponder to achieve this is most likely out of scope for short term practical 400GE/1TBE that IEEE will put into standard. So serial lights on/off much faster than 25 Gbaud runs into serious physical limitations, as some physical effects increase 4-fold when you on/off blink 2 times as fast. That's why we do not have 100Gbaud 100GE, but instead 4x25Gbaud.
Coherence appears to be the secret sauce in pushing the SnR boundaries, albeit I'm not going to pretend to even understand the physics involved, I was just lucky enough to speak to some people that do. :)
Yes, for long-haul DWDM systems coherent detection is absolutely the way to go. For short and metro reach at low cost, that is probably going to be a bit further into the future. -- Mikael Abrahamsson email: swmike@swm.pp.se