Planar lightwave circuit polarization mode dispersion compensator

We fabricated an integrated-type optical PMD compensator on a silica-based planar lightwave circuit, where an endless polarization controller and a polarization-dependent delay line are installed. We confirmed its operational principle in a 43-Gbps transmission system.

1. Introduction

Polarization mode dispersion (PMD) is becoming a serious problem in long-haul high-speed transmission systems. Since PMD varies with time, several adaptive compensators have been proposed; some are electrical /1/ and others optical /2/ –/4/. Although the electrical compensators are simple and compact, it is difficult to apply them to high-speed optical signals more than 40-Gbps because of the electric speed limit. By contrast, the optical compensators are inherently transparent, and applicable to high-speed signals. They are, however, bulky and very large.