Re: Pluggable Coherent DWDM 10Gig

[Phil Bedard <bedard.phil () gmail com>]

What are you trying to do?  Why do you need the receive side to be tuned
to a specific narrowband wavelength?  Coherent doesn't really make sense
in 10G becaue 10G long-haul is still on/off keyed and doesn't care about
phase. Coherent detectors are needed where phase of the signal is
important like long-haul 100G where multiple analog photonic signals are
mixed on the transmit side.  It also requires DSPs to process the received
information. You aren't going to put a DSP inside a SFP+ cage.  With
CFP2/CFP4/QSFP28 the optics vendors would like people to start building
the DSP onto line cards, whether it be a router or transport shelf,
because there just isn't the packaging room to make it happen.

Terastream today doesn't use integrated router optics, they use Cisco's
nV-Optical solution. The connection between the router and transport shelf
is still gray optics, but the system is managed as a single logical
entity, with a 1:1 correlation between router port and transponder.  You
"tune" the wavelength on the router because of the 1:1 correlation.
Terastream just uses passive DWDM muxes/demuxes, also part of the same
Cisco transport solution, and Cisco VOAs/amps.

-Phil



On 4/25/14, 2:59 PM, "Tim Durack" <tdurack () gmail com> wrote:

> On Mon, Apr 21, 2014 at 2:42 PM, Tim Durack <tdurack () gmail com> wrote:
>
> > Anyone know if pluggable coherent DWDM 10Gig optics exist? (I'm finding
> > no
> > such thing.)
> >
> > How about narrow-band/filtered receive 10Gig optics? (Inline FBG filter
> > receive side might be doable?)
> >
> > --
> > Tim:>
> >
> > p.s. Before you ask, DTAG Terastream has got me thinking...
>
> As a follow up, there are lots of people willing to sell various flavours
> of DWDM optics, but as I suspected, there is no such thing as a
> coherent/tuned/filtered receive 10GigE DWDM optic. All 10GigE optics are
> wide-band receive. However, you can get inline optical filters, Santec
> OFM-15 for example. Investigating...
>
> -- 
> Tim:>