High-precision fiber optic temperature monitoring system based on FBG-GaAs dual-mode collaborative measurement

This paper presents a high-precision fiber optic temperature monitoring system based on FBG-GaAs dual-mode collaborative measurement. The system innovatively implements a dual-mode collaborative mechanism utilizing a GaAs crystal FP cavity integrated with FBG. The FBG provides coarse measurement with a sensitivity of 0.011 nm/^∘C, enabling rapid temperature positioning across a wide range from -20 ^∘C to 150 ^∘C. Simultaneously, the GaAs component delivers fine measurement with a sensitivity of 0.12 nm/^∘C for high-resolution compensation. This approach resolves the spectral overlap issue that traditional FP interferometers face in wide temperature ranges. Experimental results demonstrate that the system achieves a maximum sampling rate of 6000 Hz with a temperature demodulation error of ±0.41 ^∘C, showing superior advantages in wide temperature adaptability compared to similar sensors.