Analysis of Strain Distribution and Sensitivity Improvement of Optical Fiber Coils in Disc Optical Fiber Accelerometers

Multi-turn optical fiber coils, as the key sensing components of Fiber Optic Disc Accelerometers (FODAs), significantly affect the FODA performances due to their layered structure. This paper explores the strain distribution characteristics of the optical fiber coils by utilizing the inherent properties of the FODA, supported by Finite Element Method (FEM) and high-precision Optical Frequency Domain Reflectometry (OFDR). The results indicate that the simulation outcomes are largely consistent with the OFDR measurements, accurately reflecting the strain distribution within the optical fiber coils of the FODA. This analysis dose not requires additional external force application devices and carries no risk of damaging the FODA. Based on FEM, the simulation model is employed to optimize the existing structure, proposing a multi-turn optical fiber coil fabricated from ultra-fine diameter fiber. By altering the structure of optical fiber coil to make the internal strain distribution trend uniform, the sensitivity of the FODA is increased to approximately 150% of its original value.