A feasible program of single-polarization active resonator using hollow-core photonic crystal fiber is proposed in this paper. The basic structure of HCPCF active resonator is designed, and the influence of polarization mode dispersion on the detection accuracy is analyzed with a solution being put forward using single-polarization HCPCF. Then the cross structure of photonic crystal fiber is designed, modeled and simulated by finite element method (FEM) at the wavelength of 632.8nm, and the mode field distribution in the cross-section is obtained. By designing the core size of photonic crystal fiber properly, a polarization extinction ratio of 8.4dB is achieved; therefore single-polarization propagation can be realized in the HCPCF, resulting in suppression of polarization mode dispersion of resonator and improving the theoretical gyroscope detection limit. This research is of great guiding significance to the development of HCPCF RLG.
Scale factor nonlinearity (SFN) and dynamic range (DR) are the two significant parameters used to evaluate the performance of a resonator fiber optic gyro (RFOG). The inherent SFN of an open-loop RFOG with triangular phase modulation is first analyzed theoretically, and its relationship with the DR is simulated, showing that the DR is significantly constrained by the SFN. For our system, when the SFN is 1%, the DR is less than ±82 deg/s. To decrease the SFN in a certain DR, a real-time compensation method based on a field-programmable gate array is proposed. The compensation model is set up and the compensation scheme is illustrated. With the proposed method, the SFN of the RFOG is decreased from 1.53% to 0.057% with a DR of ±100 deg/s.
A closed-loop resonator integrated optic gyro (RIOG) scheme based on triangular wave phase modulation is proposed.
Only one integrated optic modulator (IOM) is employed. Triangular wave is applied on the IOM to modulate the passing
light wave, and the feedback serrodyne wave is superimposed upon the triangular wave to compensate the resonant
frequency-difference. The experimental setup is established and the related measurements are performed. The results
show that the proposed scheme can realize the closed-loop RIOG employing an IOM, which has the advantage of
miniature size. A bias stability of 0.39 deg/s (10 s integration time) over 1 hour is achieved. Moreover, good linearity and
large dynamic range are also experimental demonstrated.
The frequency-lock (FL) accuracy of a passive ring resonator optic gyro (PROG), which is closely related to the frequency bias, determines the ultimate measurement precision of the gyro system; therefore it is particularly important to choose a proper frequency bias for the PROG to achieve excellent performance. The best performance of the PROG comes from the optimal signal-noise ratio (SNR), rather than the highest sensitivity. The relations among the SNR affected by the photon shot noise of the photodetector, sensitivity and the frequency bias of the PROG are analyzed in detail for both transmission-type and reflection-type PROGs under Lorentz function approximation in this paper, and the optimal FL frequency bias ranges are discussed. This work provides explicit theoretical guidance for the systematic optimization of the PROG.