Methodology for estimation of sensitivity to vibration of optical components based on wavelet analysis of vibration-modulated radiation

The vibrations of navigation systems, including fiber optic gyroscopes, affect the intensity of radiation passing through their optical components. This can lead to positioning errors in vehicles. The mechanism by which vibrations influence fiber optic gyroscopes and the reasons for their high vibration sensitivity are still not fully understood. This paper investigates the amplitude modulation of the optical signal caused by the vibration of passive optical components. The sensitivity to vibration is evaluated by registering optical power passing through components on an experimental stand while they vibrate at frequencies between 20 and 2000 Hz with amplitude of 5 g. The measurement results are processed using a wavelet transform and fast Fourier transform algorithm. The algorithm estimates and searches for vibration-induced modulation of transmitted radiation. Typical cases of the time sweep of signals passing through optical components are presented. The influence of vibration on transmitted radiation is demonstrated. Modulation of the optical signal passing through Y-splitters from different manufacturers is detected, manifesting as periodic changes in the measured radiation power and changes in the split ratio. An algorithm is presented that enables accelerated analysis by selecting data rationally for subsequent wavelet analysis. The proposed methodology for analyzing modulation based on wavelet analysis enables the sensitivity of optical components to vibration to be estimated and resonant frequencies for Y-splitters to be selected. This methodology enables the identification of modulation levels below 0.1 % of the initial power.