FDTD investigation of optical integration between Si3N4 and III-V compound semiconductor based waveguide

Photonic integrated circuit has recently gained significant attention due to it’s diverse innovative applications. In this paper, we investigated a passive optical coupling in a waveguide via 3D FDTD simulation. It is based on a Si 3 N 4 waveguide and a III-V binary compound test waveguide, with an amorphous Si optical bridge. It demonstrates FDTD simulations of optical field propagation and transmission. Here, the materials of the test waveguide are changed from GaAs to InAs to conduct a comparative study of binary semiconductor compounds with similar refractive index but different crystal structures. GaAs and InAs have different lattice constants, band gaps, electrical and optical properties. This waveguide, guides light using passive optical coupling. In this vertical coupling configuration light enters through Si 3 N 4 waveguide and then amorphous Si and lastly the test waveguide. Here in the test waveguide, GaAs is used and then it is changed into InAs to study efficient coupling efficiency, optical power transmission, electric field distribution and photon transmission. In this waveguide, optical coupling occurs twice. The efficiency has been observed from the second coupling event. Also, the structural parameter has been changed, and the whole phenomenon has been studied for 1310 nm (O-band) to 1595 nm (L-band). The optical transmission ranges from 92% to 98%, with an observed coupling efficiency of 33%. We found that the studied waveguide could be employed to enable an efficient optical waveguide coupling to facilitate the transmission and change of light in photonic integrated circuit.