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