Monolithic integration of Si-silica waveguide delay line interferometer and germanium photodetectors for 25-Gbit/s DPSK demodulator

A straight-shape Si-silica waveguide delay-line interferometer and Ge photodetectros(PD) are monolithically integrated for a DPSK demodulator. The device with a foot-print of 0.49 mm² and a fiber-to-PD responsitivity of 0.29 A/W successfully demodulates 25-Gbit/s-DPSK signals.