Demonstration of a folded Sagnac sensor array immune to polarization-induced signal fading.

We demonstrate a new folded Sagnac sensor array design that combines a Faraday rotator mirror and a polarization beam splitter to eliminate the optical noise pulses otherwise generated in a folded Sagnac sensor array. A depolarization scheme compatible with this configuration is also proposed and demonstrated experimentally. It is shown that this new configuration passively eliminates polarization-induced signal fading on every sensor in the array. The minimum detectable phase was measured to be approximately 1.1 microrad/square root of Hz, in agreement with theory.

[1]  Kazi S. Abedin,et al.  Application of Sagnac interferometer for measuring chromatic dispersion of installed single-mode fibres , 2000 .

[2]  M. Martinelli.  A universal compensator for polarization changes induced by birefringence on a retracing beam , 1989 .

[3]  Michel J. F. Digonnet,et al.  A Folded Configuration of a Fiber Sagnac-Based Sensor Array , 2000 .

[4]  H J Shaw,et al.  Large-scale interferometric fiber sensor arrays with multiple optical amplifiers. , 1997, Optics letters.

[5]  H. J. Shaw,et al.  Novel fiber sensor arrays using erbium-doped fiber amplifiers , 1997 .

[6]  H. J. Shaw,et al.  Optimization of large-scale fiber sensor arrays incorporating multiple optical amplifiers. Part II: pump power , 1998 .

[7]  Klaus Petermann,et al.  Performance of Lyot depolarizers with birefringent single-mode fibers , 1983 .

[8]  Sang K. Sheem,et al.  Fiber‐optic gyroscope with [3×3] directional coupler , 1980 .

[9]  Michel J. F. Digonnet,et al.  A novel fiber-optic sensor array based on the Sagnac interferometer , 1999 .

[10]  H. J. Shaw,et al.  Optimization of large-scale fiber sensor arrays incorporating multiple optical amplifiers. I. Signal-to-noise ratio , 1998 .

[11]  K. Blotekjaer,et al.  Sagnac interferometer for underwater sound detection: noise properties. , 1989, Optics letters.

[12]  H. Hodara.  Statistics of thermal and laser radiation , 1965 .

[13]  S. Knudsen,et al.  An ultrasonic fiber-optic hydrophone incorporating a push-pull transducer in a Sagnac interferometer , 1994 .