为了消除掺铒光纤放大器的放大自发辐射噪声对分布式光纤温度传感器测温精度的影响,采用精确的修正公式进行温度解调是一种有效手段.通过分析掺铒光纤放大器的放大自发辐射噪声对系统产生的影响,并将计算的中间结果代人理论公式获得了修正后的温度解调公式.实验中分别采用理论公式和修正公式对温度进行分布式测量并获得了实验数据.结果表明,修正后的温度解调公式有效补偿了掺铒光纤放大器噪声引起的误差,并显著提高了系统的信噪比和测温精度;修正公式可将系统的整体测温精度提高到1℃～2℃;此外,实验中观察到多模光纤中喇曼背向自发散射同样会出现放大现象,这与单模光纤中的情形类似,且放大喇曼自发散射依然具有理想的温度效应.%In order to eliminate the effect of amplified spontaneous emission ( ASE) noise erf Er-doped fiber amplifiers (EDFA) on the temperature measuring precision of distributed optical fiber temperature sensors, a precise modified formula is an effective means. Firstly, the influence of ASE noise in EDFA was analyzed, and then the temperature demodulation formula was modified with intermediate calculation results. Secondly, based on the theoretical and modified formula, the temperature was tested, and the results were compared. Analysis results indicate that the modified temperature demodulation formula can efficiently compensate errors due to ASE noise and improve the signal-to-noise ratio of the system and measurement precision of the temperature obviously. The experimental results show that the temperature precision is raised to 1℃~ 2℃ by using the modified formula. Moreover, amplified Raman spontaneous scattering is also observed in multimode fibers as the same as in single mode fibers and causes amplified Raman spontaneous scattering curve distortion. However, amplified Raman spontaneous scattering exhibits ideal temperature effect.
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