| Optical fiber Fabry-Perot (F-P) sensors have been developed since 1980s. Now they have been a hotspot in the field of sensing technology due to the simple configuration, high resolution, anti-electromagnetic interference and chemical resistance. The characteristics of small volume and low weight allow them to work in narrow space and harsh environment. All these advantages indicate optical fiber F-P sensors have great application potential. The development of Micro-Electro-Mechanical Systems (MEMS) fabrication technology has opened a new window for F-P cavity fabrication. In this thesis, we discussed the principle of F-P interference, the classification of optical fiber F-P sensorsand the demodulation methods. We also designed three novel optical fiber F-P pressure sensors using the MEMS processing technology such as UV lithography, magnetron sputtering, wet etching and anodic bonding.A novel optical fiber F-P pressure sensor using angle polished fiber and corrugated diaphragm is presented. The sensor has an advantage with high sensitivity. As the sensing element, corrugated diaphragm can provide a larger deflection than uncorrugatedone under the same condition. In order to obtain the best performance, we optimized the design of corrugated diaphragm. The sensor has a sensitivity of 705.64μm/MPa at the range of 0 to 0.1 MPa. MEMS micro-machining methods are employed to fabricate the sensor. The angle polished single mode fiber (SMF) is pressed in a fiber groove formed by SU-8 photoresist. The F-P cavity length is determined by the height of SU-8 photoresist which can be controlled by the speed of spin coater. Experimental results show that the sensor has reasonable linearity and low hysteresis. Since the temperature property of the structure has good repeatability and stability, temperature compensation is realized.An optical fiber pressure sensor with composite F-P cavity using a SU-8 structure and angle polished fiber is presented. Temperature compensation is realized. There are three reflective surfaces in the sensor-the interface of fiber core and cladding, the side wall of the optical fiber and the silicon diaphragm, which form two F-P cavities. One of them changes with temperature and pressure, and the other one only change with temperature. Experimental results show that the sensor has low hysteresis and high sensitivity of 60.9μm/MPa at the range of 0 to 0.1 MPa. With temperature compensation, the effect of temperature on pressure test is greatly reduced. The sensor possesses a value of application.A novel fiber F-P pressure sensor using commercial fiber flange is presented. The sensor has simple structure, low price and high reliability. With the help of the Si-glass-fiber structure, the end face of fiber can be parallel to the sensitive membrane, thus a high quality F-P interferometer cavity is formed. The glass ring is preciselypolished and bonded together with the silicon, which guarantees the gas tightness. The cavity length is determined by the length of glass ring. The sensitivity at the range of 0 to 0.1 MPais 60.9μm/MPa, which is one order of magnitude higher than the former work of our group.
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