PURPOSE: To obtain a sensor being capable of measuring simultaneously a plurality of kinds of changing physical quantities, by a method wherein a light emitted from a light source is made to branch into a reference light and two measuring lights, and the interference lights of the emitted lights of two optical fibers for measurement and of the reference light are received by two light-receiving elements.
CONSTITUTION: A light emitted from an He-Ne laser 41 is made to branch, by half mirrors 1 and 11, into one reference light deviated by a frequency (f) by means of a frequency shifter 2, and two measuring lights, The reference light emitted from an optical fiber F0 is collimated by a lens 4 and then made to branch and reflected by a half mirror 5 and a mirror 6, and the reflected lights proceed toward half mirrors 15 and 25. The measuring lights emitted from optical fibers F1 and F2 are collimated by lenses 14 and 24 respectively and joined to the emitted light of the optical fiber F0 by the mirrors 15 and 25 respectively, and they interfere with each other and proceed to photodetectors PD1 and PD2 to be received thereby. Output electric signals of these detectors PD1 and PD2 are to have the frequency (f) and phase items corresponding to a temperature and a pressure impressed.
KITAJIMA HIROSHI
YOSHIDA TOMIYOSHI
NAKATSUKA NOBUO
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