| 摘要 |
PROBLEM TO BE SOLVED: To constitute an optical fiber sensor whose manufacture is easy and inexpensive and which has high tensile sensitivity by using single mode type optical fiber formed of a core, a clad arranged around the core and a through hole arranged in the clad. SOLUTION: Retardation (phase difference) sensitivity of a polarization interference type optical fiber sensor to elongation strain largely depends on tensile stress induced birefringence Bt, and a parameter Bt (ΔL/L) (L is a length of fiber, andΔL is elongation) exterts large influence on a phase difference. Then, when single mode type optical fiber F composed of a core 3, a clad 1 arranged around it and a through hole 2 arranged in the clad 1 is used as a light sensor, since the large through hole 2 exists near the core 3, when tensile stress and circumferential directional stress are applied, since asymmetric large stress is generated in the core 3, a parameter Bt (ΔL/L) value becomes large, and large phase difference sensitivity is obtained, a highly sensitive sensor can be formed.
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