FASEROPTISCHER KREISEL.

摘要

A modulated phase difference is detected between two rays of light phase modulated by a phase modulator (24), having propagated through an optical fiber coil (17) in opposite directions and interfering with each other. A ramp voltage (Rp) controlled in polarity and frequency in accordance with the detected phase difference is generated. The ramp voltage (Rp) is applied to the phase modulator (24) to control it so that a maximum phase shift of light thereby is 2 pi k rad (where k = +/- 1 +/- 2, ...). To correct the temperature characteristic of the phase modulator, a peak value control circuit (60) creates a reference voltage corrected by a voltage detected by a temperature sensor (50) and controls the peak value of the ramp voltage by the reference voltage, thereby ensuring that the maximum phase shift of light in the phase modulator (24) is always 2 pi k rad regardless of temperature changes.