PURPOSE: To facilitate the handling, and also, to improve the temperature detection accuracy by covering and forming a clad layer consisting of a substance whose refractive index is varied due to a temperature, on the outside periphery of an optical fiber core.
CONSTITUTION: In the outside periphery of an optical fiber core 11, a first clad layer 12 of a substance whose refractive index is larger than that of the core 11, and also, which abounds in the refractive index temperature dependency is formed, and also, in the outside periphery of said first clad layer 12, a second clad layer 14 whose refractive index is smaller than that of the core 11 is formed. As for a substance whose refractive index is larger than that of the core, and also, which abounds in the refractive index temperature dependency, for forming the first clad layer 12, urethane acrylate, or ultraviolet ray curing type plastic of silicone acrylate, polybutadiene acrylate, etc. are available. In such a way, other optical elements than an optical fiber are not required at all, the wavelength of a light beam to be used is also unlimited, this sensor is compact and handled easily, and also, the measuring system is simplified and the cost can be reduced.
TSUCHIYA SHINICHI
TSUTSUI TERUAKI
HITACHI CABLE
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