CFBG-Based Linear Displacement Sensor Enabled by MXene’s Photothermal Effect

Accurate measuring of mechanical displacement is essential for most technologies. Here, we introduce a novel chirped fiber Bragg grating (CFBG) displacement sensor that enables ultra-sensitive measurement of a transverse displacement by mapping it into the phase-shift distribution of the CFBG. The displacement sensor is implemented by introducing a nonpermanent phase-shift on the CFBG with the assistance of MXene's excellent photothermal effect. The phase-shift distribution can be used as a marker on the scale, and a high-resolution spectrometer observes the phase-shift markers so that a displacement sensor can be realized. The results of the proof-of-concept experiments show that the sensitivity of the sensor can reach 0.88 nm/mm with a linearity coefficient of 0.998 over a 10 mm range, and the displacement resolution of the sensor is about 12 μm. Our scheme is intrinsically stable and could be implemented as a compact sensor, using a cost-effective sensor design. This sensor can offer aerospace, biomedical, and machining applications, especially in harsh and closed environments with strong electromagnetic interference.