光纤法珀应变传感器中传感头对中度对信噪比的影响

The effect of the inaccuracy in line of fiber optic F-P sensing head on SNR in fabry-perot sensor

分析光纤法珀应变传感器在工程应用中受到剪切应变时传感头发生相对错位对信噪比的影响,由于相对错位使得传光有效功率发生改变,进而影响到信噪比的变化,利用经典电磁场理论,建立其数学分析模型,计算机数值模拟结果表明,对中度越高,信噪比越高,当对中度接近0.1时,信噪比将趋于平稳,此时传感器将失效.

When fiber optic Fabry-Perot strain sensor undergo strain in engineering, the effect from the malposition of the sensing head on the Signal Noise Ratio（SNR） is discussed in this paper. The effect power changes with the malposition in line, and makes the SNR changeable. The mathematical analytical model is founded by using the electro magnetic theory and the numerical simulation is carried by using a computer. The results are that the larger the malposition, the higher the SNR. When the malposition in line is near to 0. 1, th SNR will tend to be relatively stable and the sensor will be ineffective. An experiment is carried to prove the theory and both results are almost identical.