optical circulator as a bidirectional one fiber solution

Mon Aug 13 20:57:25 UTC 2018

Good news about almost all optics, their Rx window is pretty wide. Meaning a 1550nm optic will activate the receiver on a 1560nm optic just fine (and probably anything in the 1500nm band).  Careful use of specialized single strand DWDM muxes (FS.com) can yield great bidi-like results with increased channel count. 

-Ben

> On Aug 13, 2018, at 10:49 AM, Eric Kuhnke <eric.kuhnke at gmail.com> wrote:
> 
> Something that is broadly the same as a coherent 100G QPSK single wavelength optical module, but in two different frequencies, and a passive CWDM mux/demux prism at each end might work. The limitation would be availability of optics for a modern 100G MSA that are both coherent and Tx/Rx at two different THz frequencies.
> 
> Or with some box and vendor equipment in between, such as: 
> 
> http://cdn.extranet.coriant.com/resources/Application-Notes/AN_Groove_Bidirectional_Fiber_74C0169.pdf?mtime=20180206023321
> 
>> On Tue, Aug 7, 2018 at 1:00 PM Daniel Corbe <dcorbe at hammerfiber.com> wrote:
>> On 8/7/2018 15:46:03, "Baldur Norddahl" <baldur.norddahl at gmail.com> 
>> wrote:
>> 
>> >Hello
>> >
>> >There is a lack of bidirectional one fiber (BIDI) options for 40G and 
>> >100G optics. Usually BIDI is implemented using two CWDM wavelengths, 
>> >one for tx and one for rx. However there is also a lack of CWDM and 
>> >DWDM options for 40G and 100G.
>> >
>> >Would it be possible to use an optical circulator like this one 
>> >(customized to 1310 nm)?
>> >
>> >https://www.fs.com/de/en/products/33364.html
>> >
>> >Combined with a traditional two fiber 1310 nm 10 km 40G QSFP module 
>> >like this: https://www.fs.com/de/en/products/24422.html
>> >
>> >The link distance would be 5 km.
>> >
>> >The optical circulator separates tx and rx by the direction the light 
>> >travels in. It would work even though both directions use the same 
>> >wavelength. There will likely be some reflection but hopefully 
>> >attenuated enough that it is regarded as background noise.
>> >
>> >Has anyone done this? Any reason it would not work?
>> >
>> >Regards,
>> >
>> >Baldur
>> >
>> 
>> The main issue you're going to run into (especially trying to plug 
>> anything into a DWDM shelf) is 40G and 100G transceivers usually emit 4 
>> lanes of traffic instead of a single lane like 10 and 1G optics do.
>> 
>> I'd imagine that's why there are so few solutions that don't involve 
>> things like OTN.
>> 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.nanog.org/pipermail/nanog/attachments/20180813/b11cd9f0/attachment.html>