Low-loss, Ultra-compact Monolithic Integration Of High-speed Polarization-diversity Photodetectors

Abstract

Polarization-selective optical devices are required for polarization-diversity coherent lightwave receivers.[l] Monolithic integration of such devices with photodetectors improves detector functionality and eliminates package complexity by reducing part count and hybrid optical interconnects. Compatibility with high III-V materials' cost, however, requires simple, high-yield processes and compact device size. We previously proposed a simple and compact integration scheme employing metal-loaded vertical couplers for polarization splitting and vertically-coupled photodiodes for O/E conversion. Initial experiments using InGaAsP/InP demonstrated satisfactory optical functionality, with 10.6 and 16dB polarization selectivity for TE and TM polarized-light.[2] Here we show how such integrated devices can be modified to achieve suitable electronic performance, including wide bandwidth and high quantum efficiency.