| 摘要 |
PROBLEM TO BE SOLVED: To provide a simple, low-cost, and high-precision optical fiber sensor capable of suppressing polarization dependence. SOLUTION: The optical fiber sensor includes a light source, a sensing section having a reflective surface whose relative distance from the end of the optical fiber varies according to physical quantities, such as, pressure and temperature, a first optical fiber for transferring light from the light source to the sensing section, second and third optical fibers respectively transferring light reflected on the reflective surface to a plurality of light-receiving sections, and a processing section for calculating the physical quantities from ratios of electrical signals coming from the light-receiving sections. Each end surface of each fiber is fixed so that the longitudinal direction of the optical fiber is at an angle ofθwith respect to the normal line of the reflective surface; the second and third optical fibers are disposed parallel to each other so that the fixed angle of the first optical fiber and the fixed angle of the second and third optical fibers are symmetric, with respect to the normal line of the reflective surface; and the first to third optical fibers use waveforms in the single mode, and a depolarizer is provided between the light source and the end surface of the first optical fiber. COPYRIGHT: (C)2009,JPO&INPIT
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