Polarization independent bidirectional fiber link using coherence multi/demultiplexing LiNbO/sub 3/ integrated electrooptical circuits

We report recent results obtained in the area of bidirectional transmissions. We demonstrate the application of coherence modulation to such transmission systems using especially designed LiNbO/sub 3/ integrated electrooptic circuits. We describe a system, formed by a pair of matched Mach-Zehnder interferometers integrated in Z-propagating lithium niobate substrate, whose peculiarity is to feature a polarization-independent behavior in the frame of digital transmissions. Considerations on crosstalk are also discussed. The experimental results deal with the demonstration of a bidirectional link with a data bit rate of 25 Mb/s.