InP-PD integration on silica-based PLC for QPSK receiver

Abstract

We review our recent progress on the heterogeneous integration of high-speed InP photodiodes (PDs) on a silica-based planar lightwave circuit (PLC) with the goal of realizing a small photonic integrated circuit (PIC) device with excellent performance. Heterogeneous integration technology is a combination of monolithic InP fabrication and angled micro-mirror etching processes, and provides low-loss optical coupling between them without any complicated optical alignment. Also, by employing 2.5%-Δ waveguides with a bending radius of 1 mm, we can reduce the chip size required for compact PIC devices. We demonstrated a dual-polarization quadrature-phase-shift-keying (DP-QPSK) coherent detector composed of a variable optical attenuator (VOA), a polarization beam splitter (PBS), eight high-speed PDs, two 90-degree optical hybrids (OHs) and micro-mirrors. Heterogeneous technology on silica-based PLCs will be an attractive way to provide compact high performance PICs for future photonic networks.