Double Coupled Dual Input Rate Sensor.
DEPARTMENT OF THE NAVY WASHINGTON DC
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This document describes an optical fiber coil rotation rate sensor including provision for equal intensity dual inputs to its fiber coil to allow the device to operate at the quadrature point and circuitry to continuously adjust the phase in order to maintain operation at that quadrature point regardless of the rotation rate. The system includes an optical fiber coil for counterpropagating light beams therethrough and an input circuit for providing a first and second equal intensity light beams for counterpropagation through the fiber coil. The input circuit comprises a laser light source, a beamsplitter for splitting light from the laser source into two equal intensity beams, first and second elongate fiber waveguides for directing the equal intensity beams to the fiber coil for counterpropagation and including two elongate coextensive close-proximity sections for light beam coupling between the fiber waveguides, and a phase shifter circuit for automatically nulling the phase-shift in the beams returning from the coil. The phase-shift required to null the returning beams is proportional to the fiber coil rotation rate. Author
- Fiber Optics and Integrated Optics