OPTICAL FIBER GYRO DEVICE

PURPOSE:To obtain a high-accuracy device high includes no output error over a wide input angular velocity range by outputting a 1st signal for driving a phase modulator and a 2nd, 3rd, and 4th signals of angular frequency which are twice, three times, and four times as high as the 1st signal from a signal generator. CONSTITUTION:The signal generator 7 outputs the 1st signal for driving the phase modulator 6 and the 2nd, the 3rd, and the 4th signals of angular frequency which is twice, three times, and four times as high as the 1st signal. Then, the output of a light receiving element 2 is inputted to the 1st-the 4th synchronous detectors 8-1-8-4 which use the 1st-the 4th signals as reference signals, the outputs of the synchronous detectors 8-1-8-4 and the angular velocity output of an angular velocity/angle arithmetic part 30 are inputted to a modulation degree computing element 9 and processed as specified, and the arithmetic output is inputted to a modulation degree control amplifier 6-1, so the modulation degree of the phase modulator 6 is held constant even when a large angular velocity is inputted.