Fiber strain sensor and system including one intrinsic and one extrinsic fabry-perot interferometer

摘要

A strain sensor (50) combines an intrinsic Fabry-Perot interferometer (IFPI) (60) with an extrinsic Fabry-Perot interferometer (EFPI) (56, 62). The IFPI (60) is between two EFPIs (56,62) and shares its two air to glass minors (58, 62). The outside edges (54, 66) of the two EFPIs (56, 64) are connected to an optical fiber (52). The strain sensor (164) can be implemented on a semiconductor chip (150). A waveguide (156) on the semiconductor chip (150) is etched to form two blocks (158) with an island section (162) between them. The two blocks (158) form the EFPI and the center section (162) forms the IFPI. A strain measurement system (100) that takes advantage of the strain sensor (50) has a laser (102) coupled to a optical fiber (106) containing one or more strain sensors (108). A coupler (104) directs the reflected light from the sensors (108) to a tunable Fabry-Perot etalon (114). The output of the tunable Fabry-Perot etalon (114) is coupled to a photodetector (116). A controller (118) monitors the output of the photodetector (116) and controls the tunable Fabry-Perot etalon (114).