摘要 |
A light source signal is amplitude modulated by a phase modulated sinusoid and passes through two directional couplers so that two beams are formed. The beams are transmitted to the ends of an optic-fiber coil for propagation therethrough in opposite circular directions. An optical phase modulator is present at one end of the coil so that a phase modulation of fixed frequency and amplitude is introduced to a first beam as it enters the coil and to the counterpropagating beam as it leaves the coil. The counterpropagating beams produce a signal at a photodetector which is a function of rotation rate. An electronic control unit is connected to the photodetector to generate a digital signal output as a frequency which is a measure of rotation rate. A feedback loop is completed by connecting a signal, produced by the control unit, to the amplitude modulated light source for nulling the phase shift due to rotation rate. |