PROPOSAL AND ANALYSIS OF AN ULTRASHORT DIRECTIONAL-COUPLER POLARIZATION SPLITTER WITH AN NLC COUPLING LAYER

We propose a novel and high-performance directional-coupler polarizati on splitter using nematic liquid crystal (NLC) as the coupling layer. The beam propagation method is used to investigate the propagation cha racteristics of the device under various conditions. Results of the nu merical calculation relevant to the design conditions are presented. B ecause of the large birefringence of NLC, a very short device length o f 140 mu m is achievable at a high extinction ratio of 28 dB.