Long Working Distance Apodized Grating Coupler

TL;DR

This paper presents a novel apodized focusing grating coupler with high efficiency and compact design, enabling efficient fiber coupling for semiconductor on insulator waveguides like GaInP.

Contribution

The paper introduces a new design method for a focusing grating coupler with apodized filling factor, period, and curvature for improved out-of-plane focusing and efficiency.

Findings

Coupling efficiency of about 45% from 2D simulations.

Total device length less than 70 μm.

Effective out-of-plane focusing for fiber coupling.

Abstract

We design a focusing grating coupler by a simultaneous apodization of the filling factor and the period. In addition to in plane focusing to the input waveguide providing a total length of less than 70{\mu}m, a further apodization of the curvature allows out of plane focusing into a fiber set 150{\mu}m away from the grating surface. The design is proposed for novel semiconductor on insulator waveguides such as GaInP. The coupling efficiency is calculated from two dimensional simulation which is about 45%.