INTEGRATED OPTICAL POLARIZATION-DISCRIMINATING RECEIVER IN GLASS

We have successfully demonstrated an integrated optical TE-TM mode dis criminator using waveguide polarizers and guided-wave photodetectors f or use in polarimetric optical sensor and positioning systems, The pho tonic integrated circuit consists of a Y-branch waveguide splitter for med by potassium-sodium ion exchange in silicate glass, Hydrogenated a morphous silicon claddings were deposited on each branch of the splitt er to act as polarizers, One output cladding was trimmed to a thicknes s which attenuated the TE polarization, while the other cladding was t rimmed to attenuate light having TM polarization, The thickness trimmi ng was accomplished using a process of localized plasma etching which allows in situ extinction optimization by monitoring transmitted light . Optical extinction ratios of up to 27 dB were demonstrated on Y-bran ch waveguides for polarizers with claddings 1.2 mm in length. The inte grated receiver was completed with the deposition of metal-semiconduct or-metal photodetectors on each of the output waveguide branches follo wing the polarizers, Amorphous silicon claddings were contacted with c hrome-gold interdigitated Schottky contacts to form the waveguide dete ctors.