Temperature-independent vibration sensor based on Fabry–Perot interferometer using a fiber Bragg grating approach

An innovative vibration sensor based on a Fabry–Perot interferometer (FPI) using fiber Bragg grating (FBG) reflectors was demonstrated in this work. The sensor was designed to be compact and easy to fabricate, independent of temperature, to overcome limitations seen in previous designs, providing an effective correction for temperature effects in FBG-based FPI (FBG-FPI) sensors. A laser source with a peak wavelength of 1547.42 nm obtained from the FBG reflective peak was used to illuminate the FBG-FPI so that the light source was always within the FBG-FPI optimum wavelength operating range of 1547.15 to 1547.80 nm. The sensor was shown to capture a 3-kHz burst signal from a signal generator in 1-, 2-, and 3-Hz intervals. In addition, the work carried out has revealed that the sensor could be used to capture sinusoidal signals at frequencies up to 9 kHz, creating a performance comparable with many existing conventional piezoelectric sensors. Furthermore, the ability to operate regardless of any ambient temperature changes [from 26.5°C (room temperature) up to 80°C] opens the way to use such a sensor system over a wide range of engineering applications taking advantage of the next generation of FBG-based FPIs.