Temperature-Insensitive Vibration Sensor With Kagomé Hollow-Core Fiber Based Fabry–Perot Interferometer

Based on Fabry–Perot interferometer, an all-fiber temperature-insensitive vibration sensor using a Kagomé hollow-core photonic crystal fiber, is investigated. The Fabry–Perot cavity is realized by splicing a ∼18.5 mm Kagomé fiber with two single-mode fibers. Owing to the essential characteristic features of Kagomé fiber, this vibration sensor possesses advantageous properties, such as compact size, enhanced sensitivity and good immunity to temperature fluctuations. It has extended single-frequency response spanning from 1 to 20000 Hz, as well as flexible detection of complex vibration signals. The experimental results show that, within a certain range of 0.2–5 m/s
²
, the output signal of the sensor changes linearly to the vibration acceleration. The temperature-induced fringe shift is also measured at 0.57 pm/°C in the range from 30 °C to 100 °C, indicating that the vibration sensing is quite insensitive to ambient temperature fluctuations. This temperature-insensitive vibration sensor shows promising potentials in structural health monitoring and environmental surveillance.