Re: AW: 80 km BiDi XFPs

[Julien Goodwin <nanog () studio442 com au>]

On 06/04/13 21:50, Thomas Weible - FLEXOPTIX wrote:
> Matt Addison [mailto:matt.addison () lists evilgeni us] wrote:
> > How much spare margin do you have? Could you roll your own with a pair
> > of mismatched (C|D)WDM XFPs and a mux on each end?
> Typically you have 23dB powerbudget for the ZR (CWDM or DWDM) - maybe +2 dB through selection of TOSA. A CWDM Mux 
> will take 2dB and a small DWDM Mux approx. 4dB  - you need two of them. This will drag your overall link-powerbudget 
> below 20dB.
>
> It might work if you add a FEC (either on the linecard or the XFP itself). This will add approx. 5dB to your 
> powerbudget of 23dB. Take a CWDM Mux and fire x-crossed on 1550 and 1570 (maybe 1530) and you will face an 
> attenuation of approx. 0,2 - 0,25dB/km. This could work and you should be able to transmit 80km to 90km. It's worth a 
> test - also to figure out if dispersion will have an impact or not.

If you're going to that effort buy a mux with an amp, and use short-haul
SFP's with FEC.

A choice I found particularly neat (I got a hold of some of their HW
architecture docs but haven't actually tried it) is the SmartOptics
"m:series", an 4/8/16/32ch PTP metro DWDM system in a 1ru box (or 2ru
for 8/32ch)

http://www.smartoptics.com/products/mseries/

MRV, BTI and others make more modular options if you want just the EDFA's.