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


> -----Original Message-----
> From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx] 
> Sent: Friday, August 08, 2008 6:17 PM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [802.3BA] Discussion on 40G for => 10 km SMF
> Mikael,
> 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.

To put this into context, a 40G serial solution running in the 1550nm
window is (dispersion) limited to a distance of only 3-4km
(significantly less than even the 10km Mikael is looking for). This
compares to a distance of 80+km at 10G .

Bottom line is that 40GE colored optics will require something other
than a simple serial solution (as Chris pointed out in an earlier

Gary ....

> Chris
> -----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 applications.
> 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