Phase modulation signal generating device for fiber-optic gyroscope

A phase modulation signal generating device for a fiber-optic gyroscope that generates a phase modulation signal to a multi-function integrated optical circuit having a phase modulator that modulates light to enter a fiber-optic coil of an interference type fiber-optic gyroscope, the phase modulation signal generating device for a fiber-optic gyroscope comprising:

• a sine wave generator that generates a fundamental sine wave of an odd-order frequency (v=(2n+1)vc, where n=0, 1, 2, . . . ) of the eigenfrequency (vc) of the fiber-optic coil and a higher-order sine wave of an odd-order harmonic frequency ((2m+1) v, where m=1, 2, 3, . . . ) of the odd-order frequency (v);
• and
• a superimposer that superimposes the fundamental sine wave and higher-order sine wave generated by the sine wave generator at a ratio using a modulation index optimized according to relative intensity noise or shot noise, or mixing noise thereof to be minimized and outputs the resultant signal to the phase modulator as a phase modulation signal.