Noise analysis and measurement of high sensitivity photonic crystal fiber-optic gyroscope

Incoherent back-reflection and backscattering in photonic crystal fiber (PCF) interferometer fiber-optic gyroscope (IFOG) was investigated experimentally by using an optical time domain reflectometer (OTDR). A method to evaluate the intensity of the incoherent back-reflected and backscattered light in PCF IFOG was proposed. With the evaluated incoherent back-reflected and backscattered light intensity, a more accurate noise model for PCF IFOG was proposed. In the model, not only the fundamental detection limits in conventional IFOG but also the extra noise arise from incoherent back-reflection and backscattering owing to the unique structure of the PCF were considered. An experimental quantitative verification of the model was provided by using a noise measurement setup. The measurement results showed that the predictions were in good agreement with the observed noise levels.