High-Sensitivity Mach-Zehnder Interferometric Fiber-Optic Temperature Sensor with PMMA Coating for New Energy Battery Thermal Management

<jats:p>To realize temperature monitoring for new-energy batteries, this work proposes a PMMA-coated Mach-Zehnder interferometer (MZI) fiber temperature sensor. Theoretical and experimental characterizations verify its thermal sensing performance. The interference spectrum redshifts as temperature increases. Between 30–70°C, the sensor achieves a maximum temperature sensitivity of 170 pm/°C. Compared with conventional fiber temperature sensors, the sensor features high stability, easy fabrication, tunable sensitivity and good linearity.</jats:p>