Compact Integrated Polarization-Insensitive Two-Channel Receiver on Silicon

We describe a polarization-insensitive two-channel receiver which utilizes a novel Mach-Zehnder interferometer on a high-index-contrast waveguide platform and integrated germanium photodetectors for access application. A fiber-to-detector polarization-dependent loss of less than 0.8 dB is demonstrated over a wide wavelength range. By packaging the receiver chip with transimpedance amplifiers, we measured sensitivities of -23.3 and -22.6 dBm for the two channels at 2.5 Gb/s and demonstrated polarization-insensitive operations.