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Proceedings Paper

SAGNAC Effect Fiber Ring Gyro With Electronic Phase Sensing
Author(s): David E. Thompson; Dean B. Anderson
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Paper Abstract

A Sagnac effect interferometer gyro using an optical fiber solenoid ring is delineated where electronic phase detection is employed as opposed to observing an optical fringe shift indicative of rotation. A balanced double-heterodyne system is employed to detect the counter-circulating optical waves derived from a single red He/Ne laser source. The laser output is frequency shifted to provide the counter-circulating signals and the heterodyne local oscillator. Two Bragg-type elasto-optic frequency shifters are employed using Te0:Si02 centered at 70 MHz, the difference of which is the IF frequency in the 10 - 100 KHz range. Hard-limited IF amplification is employed before phase detection. The rotation-induced phase shift (Sagnac effect) appears as a balanced differential phased shift between the channels. Interferometer operation using both quasi single-mode and multi-mode optical fibers with 6328A radiation has been demonstrated. High visibility Fresnel fringes due to the Sagnac effect have been observed using a 1 Km length of multi-mode fiber and a 0.46 Km length of quasi single-mode fiber. Using the 0.46 Km long fiber at 6328A with 9dB/Km loss where its single-mode cutoff is at 9400A, rotational rates of less than 0.1 degrees rotation per second are easily discerned using the balanced double-heterodyne system with electronic phase sensing.

Paper Details

Date Published: 15 December 1978
PDF: 1 pages
Proc. SPIE 0157, Laser Inertial Rotation Sensors, (15 December 1978); doi: 10.1117/12.965478
Show Author Affiliations
David E. Thompson, Rockwell International (United States)
Dean B. Anderson, Rockwell International (United States)

Published in SPIE Proceedings Vol. 0157:
Laser Inertial Rotation Sensors
Shaoul Ezekiel; G. E. Knausenberger, Editor(s)

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