Recent Progress and Future Perspective of Planar Lightwave Circuits

Channel numbers of AWGs have been dramatically increased up to 400ch in single wafer. In the multi-chip configuration (tandem AWGs), 4200ch has been achieved with 5GHz channel spacing [1]. Optical functional devices are important to solve electrical bottleneck issues. Various kinds of optical-layer signal processing devices have been developed; they are reconfigurable optical add/drop multiplexers (ROADM), dispersion slope equalizers, PMD equalizers, dynamic gain equalizers, optical label recognition circuits, temporal pulse waveform shapers, and etc. Ultra-compact and CMOS compatible silicon waveguides [2] are important for the integration of an optical component and an electronic circuit, which can improve overall system performances.