Remodulation

In the most common cases, remodulation makes use of RSOA or power splitters. It is not important to me whether or not the system works well in terms of error – that can be fixed. I’d rather to get it to work first, to send the upstream signal through a birdirectional channel and get a signal at upstream receiver.

Hi,

Here I have attached an .osd file of an implementation of a bidirectional system which makes use of coherent QAM both in downstream and upstream. When the downstream signal passes through the channel, it is splitted to two branches, with one going to the downstream receiver and the other to upstream transmitter, to be used as an optical source instead of the laser (which is the whole point of using remodulation technique, BTW). The problem is, though, that there is no upstream signal after the bidirectional fiber, as it can be seen by ‘Optical Spectrum Analyzer_2’. What is the problem?

The system error is not important for me here. I just want to have the signal. Thank you in advance!

The file:

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