Optimized 3D simulation method for modeling of out-of-plane radiation in silicon photonic integrated circuits

TL;DR

This paper introduces a fast, accurate 3D simulation method for out-of-plane grating couplers in silicon photonics, combining 2D FDTD, EIM, and Rayleigh-Sommerfeld diffraction for efficient modeling.

Contribution

The paper develops a novel simulation scheme that significantly reduces computational effort while maintaining high accuracy compared to full 3D FDTD simulations.

Findings

Electric field rms difference below 5% compared to 3D FDTD

Power flux difference below 3%

Successful design of a silicon photonic grating coupler

Abstract

We present an accurate and fast 3D simulation scheme for out-of-plane grating couplers, based on two dimensional rigorous (finite difference time domain) grating simulations, the effective index method (EIM), and the Rayleigh-Sommerfeld diffraction formula. In comparison with full 3D FDTD simulations, the rms difference in electric field is below 5% and the difference in power flux is below 3%. A grating coupler for coupling from a silicon-on-insulator photonic integrated circuit to an optical fiber positioned 0.1 mm above the circuit is designed as example.