A new method of optical coupling between waveguides and photodiodes using waveguide‐type layered optical couplers

Abstract

In an attempt to develop a waveguide‐type layered optical coupler which has the same cross‐section dimension of dielectric layers as the optical waveguide, a new optical coupling system is discussed. This system is designed to couple the flip‐chip‐mounted photodiode with the waveguide. Because the proposed couplers can be manufactured in quantity, they have the potentiality for applying to optical interconnection modules where a large‐scale and a large number of optical connections are required. The present paper discusses the performance of the waveguide‐type layered optical coupler based on the analysis by the beam propagation method (BPM) and on the experimental results. Both the power transfer from the waveguide to the coupler and the radiation process from the coupler to the photodiode are both clarified. These results indicate the optical coupling between the photodiode and the optical waveguide. Further, the optimum coupler‐structure for the maximum power transfer ratio from the waveguide to the coupler, which performance is least sensitive to the thickness error, is discussed. The coupling efficiency of 22 percent for the Gediode is obtained.