Investigation of Bias Stability Enhancement using Frequency comb source in Resonant Fiber Optic Gyroscope

Bias stability is a critical performance parameter in navigation applications. We investigate the possibility of enhancing the bias stability in a navigation grade Resonant Fiber Optic Gyroscope (RFOG) through the use of dual frequency comb source. In a conventional RFOG, a single wavelength laser source is used to generate counter propagating waves in a ring resonator whose phase difference is measured to obtain the rotation rate. However, the primary limitation of the RFOG performance is the bias drift observed due to non-reciprocal effects such as Kerr nonlinearity, Rayleigh backscattering, and environmental fluctuations. To enhance the bias stability, we have investigated an alternative approach based on a frequency comb source. By using different set of frequencies (3, 5, 7, 9 etc) for the counterpropagating waves, the above limitations can be mitigated since the uncertainty in the demodulated phase is diminished compared to a single frequency measurement leading to enhanced accuracy in the rotation rate determination. Using a theoretical model of the frequency comb-based RFOG, we have carried out simulations in Matlab and investigated the bias stability enhancement with respect to the number of comb lines used. Our simulation results shows that a bias stability of 0.01 degrees/hr can be achieved using frequency comb source with 5 fundamental modes in ring resonator.