The invention relates to an eigenfrequency tracking measurement method of a Sagnac
optical fiber ring of an
optical fiber gyroscope, and belongs to the technical field of
fiber-optic gyroscopes. The eigenfrequency tracking measurement method comprises the following steps: after going through a coupler and a Y
waveguide phase modulator, dividing light into two beams of
linearly polarized light, respectively propagating the two beams of
linearly polarized light clockwise and anticlockwise along an
optical fiber sensing ring, performing
sawtooth wave phase modulation and
square wave bias
phase modulation at the phase modulator and then returning to a Y
waveguide position for interference; after
processing, demodulating an
error signal from an FPGA (
field programmable gate array); and adjusting the frequency of a
sawtooth wave modulation
signal and the frequency of a
square wave bias modulation
signal according to the intensity of the
error signal, wherein the frequency of the
sawtooth wave signal is equal to the even
number times of the eigenfrequency, and the
error signal is zero, and at the moment, the
square wave bias modulation frequency is accurately located on the eigenfrequency, the frequency of the sawtooth
wave modulation signal is just the even
number times of the eigenfrequency, and the square wave bias modulation frequency is equal to the eigenfrequency. According to the method, the purposes of tracking measurement for the eigenfrequency of the optical
fiber gyroscope and adjustment of the square wave bias frequency onto the eigenfrequency are realized.