Phase-balance feedback implementation in ultrawideband interferometric fiber optic seismometers

Abstract To remove the technical bottleneck of fiber optic seismometers in extremely low-frequency signal detection and wide dynamic range response, this paper draws inspiration from the closed-loop control principle of conventional force-balanced feedback seismometers to design and implement an interferometric fiber optic seismometer based on phase-balanced feedback. First, the phase-balanced feedback mechanism suitable for interferometric fiber optic seismometers is systematically elucidated; second, a fuzzy adaptive proportion integration differentiation (FA-PID) controller is researched and designed, which can dynamically optimize control parameters based on the system’s operational state. This approach enhances the system’s adaptability to external environmental variations and enables high-precision, low-latency closed-loop phase feedback control for the fiber optic seismic signal detection system. Simulation comparison tests with conventional PID controller show that the designed FA-PID controller can increase the system response speed by approximately 60% and improve control precision by approximately 92%. The new approach exhibits superior performance in terms of adaptability and robustness, significantly enhancing the system’s stability and control effectiveness in complex environments. This validates the feasibility and effectiveness of the FA-PID controller in closed-loop control applications for fiber optic seismometers.