摘要 |
In order to measure the rotation rate of a rotating light path by the Sagnac effect, a pair of phase modulated coherent light beams are passed in opposite directions along the light path. After the beams have emerged from respective ends of the light path, the intensity of one of them is detected as a measurement of the phase shift which occurs between the beams along the light path. The detected output is then passed through a synchronous rectifier to produce an error signal for a control loop for the system. In a preferred embodiment, the control loop is formed by a solenoid wound around a portion of an optical fiber located along said light path. By processing the current through the solenoid, a continuous update of a scale factor for the phase shift can be achieved. Also, interference with the phase shift in the rotating object is prevented by the structural interconnection between an input/output branching device and a beam splitter for the system utilizing the combination of a monomode wave guide and a polarizer.
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