100-Gbit/s PDM-QPSK Integrated Coherent Receiver Front-End for Optical Communications

This paper describes device and integration technologies for 100-Gbit/s polarization division multiplexed quadrature phase shift keying integrated coherent receiver front-end. The silica-based planar lightwave circuits for the optical passive circuits, InP-based photodiode for the opto-electrical conversion, and InP HBT for the transimpedance amplification are used to achieve high-performance. A module-level hybrid integration technology based on a chip-scale packaged O/E converter is applied as the integration technology. The fabricated receiver front-end has a wide dynamic range of around 20 dB with a constant local power of 13.5 dBm and an excellent common-mode rejection ratio of better than -25 dB up to 25 GHz.