Pluggable Coherent DWDM 10Gig

Phil Bedard bedard.phil at
Sat Apr 26 16:07:33 UTC 2014

I'm a big fan of the Terastream setup and have done a lot of research into
it, it makes sense if the density and bandwidth needs are fairly low and
the distances not so great.  Terastream also makes use of a LOT of raw
fiber which most do not really have access to.  Right now only one router
vendor supports 100G DWDM.  We will soon see DWDM CFP available, although
the density is going to be at best half what you'd get out of using
CFP2/CPAK.  I'm intrigued by Oclaro since they say they have already been
able to do it in CFP2, and have an implementation to do 200G via a CFP2,
albeit via proprietary modulation...

DTAG has done a lot of work with various vendors for interoperable
long-haul 100G which is important.  Unfortunately many of the transport
vendors are now focused on other things now like flexgrid, flex spectrum,
MacPHY (variable rate Ethernet), superchannels, 400G, etc.  It's important
they be pointed in the "standards" direction for those things otherwise we
will be left with lots of non-interoperable implementations like we have
always had.    


On 4/26/14, 7:17 AM, "Tim Durack" <tdurack at> wrote:

>Will need amplification anyway for almost any realistic topology.
>For those who don't understand what or why, please read the Terastream PDF
>and watch the video several times, then tell me it's not a great idea :-)
>On Saturday, April 26, 2014, Julien Goodwin <nanog at>
>> On 26/04/14 16:02, Mikael Abrahamsson wrote:
>> > On Sat, 26 Apr 2014, Julien Goodwin wrote:
>> >
>> >> But you'd never send it all the waves anyway, that's far too much
>> >> across the band.
>> >
>> > Please elaborate.
>> At 3dB loss per split you'd very quickly need additional amplification,
>> at which point the ROADM is cheaper. A static split can do the 80 waves
>> in much less than the ~20dB a power split would need, and
>> >
>> >> ROADMs already solve this problem, and are available at the module
>> >> (how practically available and usable I've no idea, never needed to
>> try).
>> >
>> > Compare the price of a ROADM and a 50%/50% light splitter. Which one
>> > you think is the cheapest and also operationally most reliable?
>> Not disagreeing, I'd go with dumb static optics, nearly all the
>> "reconfigurable" optic selling points don't seem to translate into
>> actual operational benefits.

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