Introduction

In the past decade, silicon photonics is gaining rapid interests in many areas including high-bandwidth datacom, optical sensing, and biomedical research. In contrast to electronics circuit design, silicon photonics integrated circuit (PIC) design faces unique challenges, due to the rich signals and multiphysics nature of silicon photonics \cite{Bogaerts_2018}. The course Silicon Photonics Design, Fabrication and Data Analysis provided through edX aims to guide through a whole cycle of silicon photonics design, fabricate, test cycle, with deep dive into theoretical backgrounds and physical modelling of PIC components \cite{analysis}.
Mach-Zehnder interferometer (MZI) is a versatile optical component that can be found in a large variety of optical devices. By configuring various parameters of MZI, many functional optical components can be realized, such as optical filter\cite{Jinguji_2000}, switch\cite{Cheng_2018}, modulator\cite{Xiao_2013}, sensors\cite{Sep_lveda_2006}, etc.
In this report, the design of a set of silicon-on-insulator (SOI) Mach-Zehnder interferometer (MZI) is proposed. The design intention of the MZI set is to extract waveguide group index \(n_g\). Chapter \ref{668092} reviews the theoretical background and design parameters of all components within the SOI-based MZI, and Chapter \ref{983782} presents the modelling and simulation of the proposed design, and provides insights to expected results.

Theory

An minimal SOI-based MZI is composed by 1) input and output waveguides, 2) Y-branch to split or re-combine light, and 3) waveguides on each arm. These components are depicted in Fig. \ref{202795} below: