optical circulator as a bidirectional one fiber solution

Eric Kuhnke eric.kuhnke at gmail.com
Mon Aug 13 17:49:11 UTC 2018

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:


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.
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