Analysis of noise failure characteristics for superluminescent diode fiber-optic gyroscopes in space applications

Noise failure, particularly due to random walk error (RWE) degradation behavior, is one of the critical failure modes for fiber-optic gyroscopes (FOGs) in space applications. In this paper, firstly, the analytical model of RWE is presented and the affected parameters are listed according to the gamma irradiation damage mechanism. In addition, the influence of temperature is also included. The deterioration of affected parameters is determined through a ⁶⁰Co radiation experiment on optic and optoelectronic components. Based on the parameters' deterioration range and assumed distribution properties, their importance to the noise failure is calculated through the Sobol method, a global sensitivity analysis method. In the computation steps, the Latin Hyper Sampling (LHS) based Monte-Carlo numerical simulation technique is adopted. It is determined from calculation results that the detected light power (DLP) is the noise failure characteristic which is the most sensitive parameter in the space environment. Finally, another ⁶⁰Co radiation experiment with the same conditions is performed on a superluminescent diode (SLD) FOG. The original noise degradation behavior is compared to the simulated RWE, calculated according to DLP, and the result shows that they follow trend almost identical. This supports the conclusion that DLP is the most sensitive noise failure characteristic for SLD-based FOGs.