Title:
OPTICAL-FIBER SENSOR SYSTEM
Document Type and Number:
Japanese Patent JP3247602
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a system, which can demodulate the signal including the physical quantity detected by an optical-fiber sensor without the effects of the fluctuation in frequency shift and the like, and can output the result.
SOLUTION: A modulating-signal generator 10 outputs the sine wave signal having the angular frequency ω0 and a reset signal in synchronization with the sine wave signal. A light source 20 outputs the frequency modulated optical signal based on the sine wave signal from the generator 10. A frequency-shift measuring instrument 30 receives the optical signal from the light source 20, receives the reset signal from the generator 10 and obtains the signal indicating the maximum frequency shift νd of the optical signal from the reset signal. An interferometer 40 outputs the optical- intensity signal based on the phase difference between two optical fibers in accordance with the optical signal from the measuring instrument 30. An OE converter 50 outputs the electric signal I=A+Bcos[Ccosω0t+&phiv (t)] based on the optical intensity signal from the interferometer 40. A demodulator 60 receives the sine wave signal from the generator 10, receives the I signal from the converter 50 and receives the νd signal from the measuring instrument 30, obtains the signal of X=B2.J1(C).J2(C).&phiv (t) in accordance with the νd and the I signal, obtains the signal of Y=J1(C).J2(C) corresponding to the &Ngr d and I signals, divided X by Y and outputs the signal of Z=B2.&phiv (t).
Inventors:
Ryosawa Sato
Application Number:
JP1084996A
Publication Date:
January 21, 2002
Filing Date:
January 25, 1996
Export Citation:
Assignee:
Oki Electric Industry Co., Ltd.
International Classes:
G01J9/02; (IPC1-7): G01J9/02
Domestic Patent References:
| JP7253355A | ||||
| JP6266734A | ||||
| JP22728A | ||||
| JP6109530A |
Other References:
Ａ．Ｄａｎｄｒｉｄｇｅ，Ａ．Ｂ．Ｔｖｅｔｅｎ，Ｔ．Ｇ．Ｇｉａｌｌｏｒｅｎｚｉ，Ｈｏｍｏｄｙｎｅ Ｄｅｍｏｄｕｌａｔｉｏｎ Ｓｃｈｅｍｅ ｆｏｒ Ｆｉｂｅｒ Ｏｐｔｉｃ Ｓｅｎｓｏｒｓ Ｕｓｉｎｇ Ｐｈａｓｅ Ｇｅｎｅｒａｔｅｄ Ｃａｒｒｉｅｒ，ＩＥＥＥ Ｊｏｕｎａｌ ｏｆ Ｑｕａｎｔｕｍ Ｅｌｅｃｔｒｏｎｉｃｓ，米国，Ｖｏｌ．ＱＥ−１８，Ｎｏ．１０，１６４７−１６５３
Attorney, Agent or Firm:
Takao Katori