Monolithic InP Dual-Polarization and Dual-Quadrature Coherent Receiver

We realized a monolithic dual-polarization, dual-quadrature coherent receiver with balanced detection on InP using a single epitaxial step. It monolithically integrates the polarization splitters, 90-degree hybrids, and balanced photodiodes in 4. 1 mm2. We demonstrate reception of 112-Gb/s polarization-division multiplexed quadrature phase-shift keying with 17.3-dB optical signal-to-noise ratio at 10-3 biterror rate.