Birefringence control of silica waveguides on Si and its application to a polarization-beam splitter/switch

A novel polarization-beam splitter/switch with a Mach-Zehnder interferometer configuration was fabricated using a silica-based planar lightwave circuit (PLC) on a silicon substrate. The polarization-beam splitter/switch was realized by accurately controlling the waveguide birefringence and the phase state by laser trimming two kinds of stress-applying amorphous silicon film with widths of 50 /spl mu/m and 95 /spl mu/m. Fiber-waveguide-fiber insertion loss of 0.5 dB and crosstalk attenuations of over 25.6 dB were attained.< >