MEMS Infrared (IR) Optical Sensor

Abstract

Thisthesis aims to study the development of Fourier Transform InfraRed (FT-IR) based multi gas sensor using theMicro-Electro-Mechanical System (MEMS)technology. For this purpose, we developed a Mid-InfraRed (MIR) MEMS FT-IR spectrometer based on Deep-Reactive-Ion-Etching (DRIE) technology over Silicon-On-Insulator (SOI) wafer. Demonstration of the gas sensing in both the Near-InfraRed (NIR) and MIR ranges has been achieved with high Signal-to-Noise Ratio (SNR) and, for the first time to the best of our knowledge. Novel interferometer archi-tecture is also introduced and designed based on the spatial splitting/combining using Multimode Interference (MMI) in hollow optical waveguides. The thesis is divided into six chapters as listed below: Chapter 1: This chapter gives a brief introduction of the motivation, objectives, major contribu-tions and organization of the thesis. Chapter 2: This chapter presents a review of the main concepts related to gas sensors and the MEMS technology used in implementing the proposed solutions. Wediscuss the gas sensors market, their different technologies and gas phase spectra in the IR range at the beginning of the chapter. Next, Silicon-based MEMS FT-IR spectrometer tech-nology is summarized showing the different MEMS technologies, along with a brief description of MEMS FT-IR spectrometers and NIR MEMS spectrometers.