High-sensitivity fiber interference strain sensor based on polarized mode coupling and TFBG

A higher sensitive sensor can provide more precise measurements in industry and research applications. Sagnac loop structure is a significant interference structure in optic fiber sensors for strain measurement. In this research, we propose a sensor structure that links a commercial Panda PMF to a 4° TFBG. With an analysis of the sensitization effect of TFBG to the interference sensors, there will be a significant enhancement of sensitivity. Based on the analysis, we demonstrate a sensor that combined TFBG with PMF to enhance the sensitivity. When a strain affects the sensor, the spectra will shift towards a longer wavelength direction. When a strain affects the sensor, the spectra will shift towards a longer wavelength direction. The proposed sensor can provide a sensitivity up to 51.9pm/ffff and 50.5pm/ffff. Meanwhile, it can measure the temperature independently on a sensitivity of 8.56pm/℃