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?)
As a follow up, I did not miss a zero. TenGig. If you want to know why:
https://ripe67.ripe.net/presentations/131-ripe2-2.pdf
(I'll take 100Gig once I can get the optics for less than the cost of a
v.nice sports car...)
You can get 100G-LR4 CFP for ~10k from good vendors. You can get them sub-10k from china what i'm hearing, but those failure rates are higher..
- Jared
As another follow-up, coherent 'cos I want tuned receive as well as
transmit, so the WDM system can be truly "colorless" and "directionless",
plus the nice high CD limit would be great.
Maybe I should ask for a pony too? 
Not sure what platform you are working with but does the ONS-SC+-10G-C ppm help in your situation?
- Ed
As a follow up, I did not miss a zero. TenGig. If you want to know why:
https://ripe67.ripe.net/presentations/131-ripe2-2.pdf
(I'll take 100Gig once I can get the optics for less than the cost of a
v.nice sports car...)
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...
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
I'm trying to build "colorless" "directionless" with passive power
couplers/splitters plus EDFA. DTAG are doing it with 100G. I think it's
doable with 10G. Will see. Interesting experiment either way, right?
(I'm betting DTAG would use integrated pluggables if they could. They don't
appear to be fans of traditional systems.)
What are you trying to do? Why do you need the receive side to be tuned
to a specific narrowband wavelength?
Because he doesn't want to use filters. A coherent receiver s like a FM radio, you can tune what it listens so. So if you send it all waves the receiver can decide what to listen to.
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.
If you're today building a new DWDM system, putting in dispersion compensation isn't something you want to do really. Having pluggable coherent 10G would make a lot of sense for some.
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.
That is correct, but the plan is to have integrated optics. It just isn't available yet. The plan is to make 100G so cheap you can use it everywhere, which includes actually having a royalty free standard for 100G including FEC.
Ask your router vendor to support STUPI AB
But you'd never send it all the waves anyway, that's far too much loss
across the band.
ROADMs already solve this problem, and are available at the module level
(how practically available and usable I've no idea, never needed to try).
But you'd never send it all the waves anyway, that's far too much loss across the band.
Please elaborate.
ROADMs already solve this problem, and are available at the module level
(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 do you think is the cheapest and also operationally most reliable?
But you'd never send it all the waves anyway, that's far too much loss
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 level
(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 do
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.
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
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.
-Phil