optical circulator as a bidirectional one fiber solution

Tue Aug 7 19:58:56 UTC 2018

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.