Fabrication of InP-PDs on Silica-Based PLC Using Heterogeneous Integration Technique

The extension of an optical transmission system with a combination of quadrature phase-shift keying and a digital coherent technique has led to the need for economical and compact receivers. In this paper, we demonstrate the heterogeneous integration of InP PDs on a silica-based planar lightwave circuit (PLC). By utilizing adhesive InP chip bonding and tilt dry-etching, we have successfully fabricated high-speed photodiodes (PDs) and a low-loss micro-mirror on a small integration area on the PLC. We have also evaluated the receiver performance. We realized 32 Gbaud DP-QPSK signal demodulation using a compact coherent receiver PLC integrated with eight high-speed PDs, a monitor PD, a polarization beam splitter, two optical 90° hybrids, a variable optical attenuator and micro-mirrors.