Type of Document	Master's Thesis
Author	Fang, Xiaojun
URN	etd-01262010-020150
Title	Sapphire fiber based high temperature extensometer
Degree	Master of Science
Department	Electrical Engineering
Advisory Committee	Advisor Name Title Claus, Richard O. Committee Member Murphy, Kent A. Committee Member Wang, Anbo Committee Member
Keywords	Materials at high temperatures
Date of Defense	1994-05-05
Availability	restricted
Abstract New sapphire fiber based sensor structures for high temperature strain measurement are proposed and studied in this report. The self-mixing interferometry has been studied and tested. The advantage of this technique is the source coherence insensitivity and direction distinguishment capability. Fringes of the self-mixing interferometer built with standard multimode fiber and sapphire fiber were observed. The application of this technique to static strain rneasurement seems difficult to stabilize, whereas its implementation to acoustic sensing with single-mode fiber coil as the sensing component will be very interesting. The approach by Moire interferometry and equal-path coherence matching interferometer are two promising methods for high temperature displacement measurement. The advantages of the Moire interferometer are source coherence independence and large measurement range. The advantage of coherence matching absolute interferometer is its simplicity in sensor structure. The structures of coherence matching methods and multiplexing techniques are generalized. From this research, we can conclude that the sapphire fiber based high temperature extensometer may be realized by different methods.
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