Resonator photonic crystal fiber optic gyro with back-reflection error suppression using biased sawtooth wave modulation technology

•Biased sawtooth wave modulation is verified to eliminate RPCFOG’s back-reflection.•The back-reflection leads to error in a triangular waveform phase modulation RPCFOG.•There is an optimum frequency between 100–600 Hz to suppress back-reflection error.•Bias stability is effectively improved to 5.9 deg/h by suppressing back-reflection. A biased sawtooth wave modulation technology is demonstrated to eliminate back-reflection errors in a resonator photonic crystal fiber optic gyro (RPCFOG) as caused by the interface between the hollow-core photonic crystal fiber (PCF) and the polarization-maintaining fiber (PMF). The theoretical study indicates back-reflection noise leads to errors in the triangular waveform phase modulation RPCFOG. The parameters of the triangle wave and biased sawtooth wave are theoretically and experimentally discussed. The results show there is an optimum triangular waveform amplitude corresponding to a maximum sensitivity for the RPCFOG. An optimal sawtooth wave frequency range of 100–600 Hz can significantly suppress the back-reflection errors. Finally, a RPCFOG prototype is assembled, static and dynamic tests are conducted to investigate its performance. With the biased sawtooth wave modulation technology, the back-reflection errors are significantly suppressed and RPCFOG’s bias stability is effectively improved to 5.9 deg/h.