Investigation of evanescent coupling between SOI waveguides and heterogeneously-integrated III–V pin photodetectors

Integrating III-V materials on Si is a promising candidate to realize both passive and active optical functions on a single silicon chip. We have developed this heterogeneous integration technology by means of an adhesive die-to-wafer bonding process under a low temperature. In this paper, efficient evanescent coupling between SOI waveguides and heterogeneously-integrated III-V pin photodetectors is proposed. The serious absorption by p-InGaAs and metal contact layers are greatly reduced by introducing a central opening on these layers. The thickness of the i-InGaAs layer is also optimized towards efficient absorption.