Temperature-Insensitive, Wide-Range Optical Fiber Vibration Sensor Based on Dispersion-Compensated Fiber

Abstract

Vibration detection plays a vital role in the safety monitoring of engineering areas such as structural deformation of large buildings and railway tracks, and oil and gas spills. Herein, a temperature-insensitive optical fiber vibration sensor based on Mach-Zehnder interference is proposed and validated, which is achieved by utilizing a dispersion-compensated fiber (DCF). Specifically, single-mode fiber (SMF) is fused to both ends of a DCF to form an optical fiber vibration sensor, which is SMF-DCF-SMF (SDS) sensor. Under this sensing structure, this sensor’s vibration sensing characteristics, amplitude-frequency response, stability, repeatability and temperature-insensitive characteristics are investigated. The sensor can measure vibration frequency signals in the large frequency range of 0.1 Hz to 47 kHz by intensity demodulation. When the vibration frequency is 600 Hz, the maximum signal-to-noise ratio (SNR) of the sensor reaches 69 dB. In addition to that, the sensor can capture low amplitude vibration frequency signals down to 0.01 V. The proposed sensor has a wide measurement frequency range that effectively reduces temperature cross-sensitivity, and it has the advantage of being compact, low cost and easy to manufacture, with potential applications in health inspections, machinery and building saturation.