Title:
OPTICAL FIBER SENSOR
Document Type and Number:
Japanese Patent JPH03264801
Kind Code:
A
Abstract:
PURPOSE:To detect the slight displacement of only a sensor part highly accurately by using both an optical resonator wherein the length of the resonator and the inner refractive index are changed in correspondence with the change in physical quantity of a material to be measured and another optical resonator which can realize the same resonating conditions as the above described resonator together. CONSTITUTION:The light from a laser light source 11 is inputted into an optical resonator for a sensor 30. Then the reflected light X is received with a detector 14. The electric signal from the photodetector 14 is controlled with a driving circuit 12 so that the electric signal has the minimum value all the time. The transmitted light Y from the resonator 30 is made to correspond to the resonant frequency all the time. Then, the transmitted light Y from the resonator 30 is inputted into a detecting optical resonator 50. Two resonators 30 and 50 are constituted so as to have the same characteristics. Therefore, the power of the transmitted light has the maximum value when the interval between partial transmitting mirrors M1 and M2 is equal to the interval between mirrors M3 and M4 under the same refractive index condition. Then, the resonator 50 detects 62 the transmitted light Y, and the mirror M3 and M4 and the interval between the mirrors M1 and M2 are kept at the equal interval. When the displacement of the interval between the mirrors M3 and M4 is measured 61, the displacement of the resonator 30, i.e. the interval between the mirrors M1 and M2, can be remotely measured.
Inventors:
INOUE YUKIHISA
Application Number:
JP6494490A
Publication Date:
November 26, 1991
Filing Date:
March 15, 1990
Export Citation:
Assignee:
YOKOGAWA ELECTRIC CORP
International Classes:
G01D5/26; G01B9/02; G01D21/00; G02B6/00; (IPC1-7): G01B9/02; G01D5/26; G01D21/00; G02B6/00
Attorney, Agent or Firm:
Masayasu Watanabe