| 摘要 |
The invention is a method and apparatus for quantitatively characterizing the pr essure induced nonreciprocity of a fiber-optic coil where the pressure-induced nonreciprocity i s a property of a fiber-optic coil which pertains to the degree to which light beams , initially in phase, differ in phase as a result of traversing the fiber-optic coil in reverse direct ions while the fiber-optic coil is being subjected to a time-varying pressure. The method compr ises the steps of applying time-varying pressure to the fiber-optic coil for a predetermined time period, measuring the phase difference of light beams traversing the fiber-optic coil in reverse d irections during the predetermined time period, and obtaining a measure of the nonreciprocity of the fiber-optic coil utilizing the measured phase difference. If the time-varying pressure is specifi ed by a first function of time, the measure of the nonreciprocity is the integral over the pre determined time period of the product of a second function of time and either (1) the phase diff erence of light beams traversing the fiber-optic coil in reverse directions during the predeterm ined time period or (2) the integral over time of the phase difference. The second function is ch osen such that the measure of the nonreciprocity has a signal-to-noise ratio of at least one. Prefe rably, the second function is (1) an approximation of the time derivative of the first function if the product involves the phase difference or (2) an approximation of the first function if t he product involves the integral of the phase difference. The invention also includes the apparatus for practicing the method.
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