Backscattering noise is an important factor to restrict the accuracy of resonator fiber optic gyroscope.The investigation on the lightwave signal in one loop of the gyro system was conducted.According to the expansion of phase modulation spectrum and optical field overlapping method,the transmission characteristics of fiber ring resonator were analyzed.The carrier component could introduce backscattering noise in the gyro system.The amplitudes of carrier component were simulated and analyzed,which showed that triangular wave modulation was superior to sinusoidal wave modulation.To suppress carrier component,the self-heterodyne carrier suppressed system was set up.The triangular wave and sinusoidal wave were applied to the phase modulator,respectively.The experiments show that carrier suppressed ratio of triangular wave modulation could reach 64.3 dB,which is 6 dB higher than sinusoidal wave modulation.The experimental results are consistent with the theory.Applied to the gyro system,carrier suppressed degree of the output signal is bigger,the fluctuation is smaller,and the gyro output is more stable using triangle wave modulation.