Exploring Transmission System Vibration Monitoring Using an Optical Fiber Fabry-Perot Bragg Grating Cavity

This paper presents a Fabry-Perot cavity Bragg grating (FP-FBG) technique for vibration monitoring. The FP-FBG is created by placing two identical and uniform Fibre Bragg Grating (FBG) with the same Bragg wavelength to produce a Fabry-Perot (FP) cavity between them. This has the effect of enhancing the vibration monitoring through tailorable enhancement of the spectral response, which scales proportionately with relative grating spacing. In this work, a single fibre containing four FPFBG of varying cavity sizes (4mm-72mm) was fabricated and tested on both a square meatal plate mounted on a mechanical shaker and bearing test rig to test the overall sensitivity of FP-FBG. The cavity size of the FP-FBG and physical positioning was investigated. The findings so far indicate that overall, FP-FBGs are effective at vibration monitoring, and initial tests are shown to detect the shaft rotation speed from a ball bearing with no faults. Future work shall look at FP-FBG capability to detect faulty bearing conditions and design parameter further.