| 摘要 |
PURPOSE: To correctly measure the temperature, refractive index and physical amount of an object to be measured in a simple constitution, by comparing a branching ratio obtained with the use of two different measuring wavelengths with refractive indexes and calibration rates of the refractive index and temperature obtained beforehand for the measuring wavelengths, and obtaining a correlation of the refractive index and temperature. CONSTITUTION: When signal lights of different measuring wavelengthsλ1 ,λ2 are sent into an optical branching device 10 from light emitting devices 30A, 30B, a part or the whole of the lights move to optical fibers f2 , f1 at the opposite side due to the refractive index of an object to be measured (e.g. wax including oil) present in the periphery of an optical coupler 12, to be separated again to wavelengthsλ1 ,λ2 by spectroscopes 35, 36 and detected by photodetectors 31, 33 and 32, 34, respectively. Branching ratios R1 , R2 are calculated by a signal-processing means. The branching ratios R1 , R2 are compared/processed with previously obtained refractive indexes and temperature calibration data at the two measuring wavelengthsλ1 ,λ2 . Two pairs of relations between the temperature and refractive index (the amount of oil represented by the refractive index) of the object (wax) to the branching ratios R1 , R2 are accordingly obtained.
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