Phase-modulated fiber optic Fizeau interferometer for measuring shock induced vibration

Due to its simplicity, low cost, safety, and high precision, the fiber displacement interferometer has emerged as a highly promising and feasible method for measuring shock-induced vibrations. However, the harsh environments associated with such shocks pose significant challenges, including the need for resistance to fluctuations in light intensity, immunity to disturbances in the transmission fiber, and the capacity to conduct large-range, high-speed bidirectional measurements. To our knowledge, no existing methods adequately address all these requirements. This paper proposes a phase-modulated fiber Fizeau interferometer specifically designed to simultaneously tackle these challenges in the context of shock-induced vibrations. Through both theoretical and experimental analyses, we demonstrate the testing capabilities and effectiveness of this approach, as well as the deviations that may arise. Furthermore, we present strategies to mitigate these deviations and analyze the impact of these methods on measurement errors.