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Re: [802.3BA] Discussion on 40G for => 10 km SMF


Your proposal for an easy to develop 40GE 8 wave transport might benefit
from additional technical due diligence.

With 20nm spacing, it is not possible to get 8 wavelengths into the
1310nm window; there are only 5 wavelengths available. In any case,
other then for the 1311nm wavelength, all other CWDM wavelengths (in all
bands) have severely limited reach because of 40G dispersion effects.


-----Original Message-----
From: Mikael Abrahamsson [mailto:swmike@xxxxxxxxx] 
Sent: Friday, August 08, 2008 2:55 PM
To: Chris Cole
Cc: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] Discussion on 40G for => 10 km SMF

On Fri, 8 Aug 2008, Chris Cole wrote:

> There is nothing about any approach being considered for 40GE 10km SMF
> that helps DWDM better then the other being considered.

I am not primarily talking about DWDM, I am talking about 10km (and 
perhaps up to 40km) SMF light with CWDM wave spacing (20nm) for metro 

Enabling fairly easy development of 40GE 8 wave transport without 
transponders (colored optics directly into external CWDM mux) tips the 
balance for me in favor of 40GE serial, if cost projections are similar 
for 40GE serial vs 4x10GE CWDM.

Mikael Abrahamsson    email: swmike@xxxxxxxxx