OPTICAL FIBER ROTATION SENSOR

Japanese Patent JP3156126

B2

PROBLEM TO BE SOLVED: To eliminate the influence of amplitude modulation by modulating the phase of light wave, separated and propagated in an optical fiber strand, in reverse directions to a detecting loop, with specific frequency constant in phase difference.
SOLUTION: Light from a light source 10 is propagated to a detecting loop 14 through an optical fiber strand 12 with fiber directional couplers 26, 34, a polarizer 32, a photo detector 30, a phase modulator 38, and the like in a path. Input light is separated into two waves propagated in reverse directions by the couplers 26, 34 and coupled again upon crossing the loop 14. The detector 30 receives an optical signal polarized in the same way as the loop input light by the polarizer 32 and outputs a signal proportional to the rotating speed of the loop 14. The modulator 38 is provided with a PZT cylinder so as to modulate the phase of a pair of light waves, passing through the loop 14, with specific modulation frequency to make phase difference 180°, in response to a modulation signal from a generator 40. With this constitution, only the reference frequency of an optical output signal is detected, and influence caused by amplitude modulation is eliminated.

Shaw, Herbert John
Refever, Elbay Sea
Burg, Ralph Allan

JP30888497A

April 16, 2001

November 11, 1997

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Board of Trustees of the Leland Stanford Junior University

G01B9/02; G01C19/64; G01C19/72; G01P3/36; (IPC1-7): G01C19/72; G01P9/00

JP5694680A

【文献】英国公開2050598(GB,A)

Masao Okabe (4 others)

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