High-Sensitivity Strain and Temperature Simultaneous Measurement Sensor Based on Multimode Fiber Chirped Long-Period Grating

A multimode fiber chirped long-period grating (MC-LPG) is proposed and studied as a sensor for simultaneous measurement of strain and temperature. This sensor consists of linear chirped multimode fiber and fixed-length single-mode fiber. The numerical analyses of the transmission spectrum and coupling mode are carried out to obtain appropriate period arrangement. The experimental results are in good agreement with the theoretical results. The chirped period arrangement induces a transmission spectrum with double peaks. Therefore, the simultaneous measurement of strain and temperature is realized by observing the wavelength shift of the two peaks. In addition, the high sensitivity of two resonance peaks provides a good resolution for the sensor.