The multi/demultiplexers use filtering, polarizing and phase retarding means to combine and split 4 optical channels, spectrally close to each other (821, 827, 833, 839 nm) with an high isolation ratio. The spectral isolator using similar means shows 3 paths : transmitting, communication and stracking. In nominal mode it transmits the MUX channels, receives the 870 nm communication channel and divides it into a given apportionment ratio to provide the tracking function. In calibration mode it connects the transmit path (MUX) to the tracking path. The performances of these equip ments require to quality optical components and technologies (coatings, polishing, assembling...). Part of these activities have been funded by CNES contract.