Optimization of high responsivity waveguide photodiode with a thin absorption layer

Abstract

The optimization of a waveguide photodiode (WGPD) having a thin absorption layer is discussed. With an absorption layer thickness of less than 0.1μm, responsivity of 1.09A∕W was achieved for lensed-fiber coupling. For flat-ended fiber coupling, responsivity of 0.93A∕W was achieved. An absorption layer thickness of more than 100Å is required for high responsivity and low polarization dependency. A formula for frequency response in a WGPD with a thin absorption layer is also obtained. This formula gives the optimized WGPD structure for high speed operation with high responsivity.