Temperature demodulation technology of distributed optical fiber temperature sensors based on EDFA

In order to eliminate the effect of amplified spontaneous emission(ASE) noise of 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.