Miniaturized Optical Fiber Inline Interferometers for Chemical Sensing
This chapter reviews the miniaturized optical fiber inline interferometers for chemical sensing based on the detection of composition variation induced refractive index changes. When used as chemical sensors, these miniaturized devices have the common advantages of small size, all-glass ruggedized structure, high sensitivity, fast response time, and large dynamic range. These advantages make them particularly attractive for real-world applications where, in situ, continuous monitoring is required. Specifically, two general types of interferometers are reviewed including the low-finesse Fabry-Perot interferometer and the core-cladding mode interferometer. The operation principles of these two types of interferometers are described. The signal processing methods are discussed. The representative structures, fabrication methods, and application examples of each interferometer type are provided with certain level of details. The advantages and disadvantages of each sensor structure are also highlighted in the discussions, with the hope that innovative researches will be stimulated to solve the technical challenges and explore future applications of these devices.
KeywordsInterference Fringe Interference Signal Photonic Crystal Fiber Core Mode Refractive Index Change
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