A Polarization-Insensitive Coherent Lightwave System Using Wide-Deviation FSK and Data-Induced Polarization Switching.

We present a technique wherein polarization-insensitive heterodyne detection is achieved through data-induced polarization switching. The polarization switching is brought about by inserting a passive, birefringent optical device in the path of the transmitted FSK signal. The experimental results show that this technique suffers a power penalty of 3 to 4 dB when compared with a conventional FSK system with perfectly matched polarizations. This compares well with the expected penalty of 3 dB. This approach uses a single optical receiver and no additional receiver electronics, which could be a significant advantage for local- area networks.