Compact Integrated Polarization-insensitive 1490 nm / 1555 nm Receiver on Silicon

We describe a polarization-insensitive 1490 nm / 1555 nm wavelength demultiplexer receiver which utilizes a novel Mach-Zehnder interferometer on high-index-contrast waveguide platform and integrated germanium photodetectors. 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 dBm and -22.6 dBm for the two channels at 2.5 Gbps and demonstrated polarization-insensitive operations.