الفهرس 
Motivation and Objectives
MEMS INFRARED (IR) OPTICAL GAS SENSOR RE-VIEWOnly 14 pages are availabe for public view
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Abstract
This thesis aims to study the development of Fourier Transform InfraRed (FT-IR) based multi gas sensor using the Micro-Electro-Mechanical System (MEMS) technol-ogy. For this purpose, we developed a Mid-InfraRed (MIR) MEMS FT-IR spectrome-ter 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 architecture 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. We discuss 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.
Chapter 3:
This chapter introduces a novel interferometer design based on MMI-based wave-guide. Firstly, we explain briefly the theory of MMI waveguides and then follow by discussing the interferometer architectures, focusing on the MMI-based splitter and combiner. Secondly, we deal with the design optimization of the interferometer geom-etry and the metallization of the waveguide sidewalls. Thirdly, we discuss the pro-posed MMI-based interferometer designs. Finally, we present the fabricated interfer-ometer along with the characterization results of the beam splitter as well as the overall interferometer.
Chapter 4:
This chapter proposes a miniaturized MIR MEMS FT-IR spectrometer based on DRIE technology over SOI wafer, for the first time to the best of the author’s knowledge. The MEMS FT-IR spectrometer system is described and the different system components are discussed. Finally, the experimental results of the developed spectrometer are presented.
Chapter 5:
This chapter studies the development of gas sensing using miniaturized MEMS FT-IR spectrometer with miniaturization limitations of SNR and spectral resolution. Then, we present and compare the experimental results for Acetylene (C2H2), Carbon Diox-ide (CO2) and water vapor (H2O) sensing in the NIR and MIR ranges .
Chapter 6:
This chapter gives the conclusion of this thesis and introduces several recommenda-tions and suggestions for the future work.