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瑞利布里渊光时域分析系统具有单光源、单端工作、非破坏的优点,为了解决系统信噪比与空间分辨率之间的矛盾,将编码技术应用到瑞利布里渊光时域分析系统中,可以在保持空间分辨率不变的前提下提高系统信噪比。提出了基于雪崩光电二极管检测和Simplex编码的瑞利布里渊光时域分析系统,系统中的随机散粒噪声功率和信号功率有关,而热噪声功率主要取决于雪崩光电二极管光电检测器的性能、与信号功率无关。由系统中与两种噪声相关的电流波动的方差和Simplex码的编解码规则可得编码系统的均方误差,由此推导了系统信噪比和编码增益公式。随着编码长度的增加,编码增益会逐渐增大并在某一编码长度后趋于稳定,因此系统存在最佳编码长度,最终推导了最佳编码长度公式,并对信噪比和最佳编码长度进行了MATLAB仿真。仿真结果表明,在基于Simplex码的瑞利布里渊光时域分析系统中,当脉冲基底1阶边带产生的瑞利散射光功率为0.5mW时,随编码长度的增加,编码增益逐渐增大并趋于稳定值6.69 dB,系统的最佳编码长度为63 bit。
Rayleigh Brillouin optical time-domain analysis system has the advantages of single light source, single-ended work, non-destructive, in order to solve the contradiction between the system SNR and spatial resolution, the encoding technology is applied to Rayleigh Brillouin light Domain analysis system, you can maintain the same spatial resolution under the premise of improving the signal to noise ratio. A Rayleigh Brillouin optical time-domain analysis system based on avalanche photodiode detection and Simplex coding is proposed. The random shot noise power is related to the signal power. The thermal noise power depends on the performance of the avalanche photodiode photodetector , Has nothing to do with the signal power. The mean squared error of the coding system is obtained from the variance of the current fluctuation associated with the two noises in the system and the code rule of the simplex code, and the system signal-to-noise ratio and coding gain formula are deduced. With the increase of the coding length, the coding gain will gradually increase and tends to be stable after a certain coding length. Therefore, the optimal coding length exists in the system and the optimal coding length formula is finally derived. The SNR and best coding Length of the MATLAB simulation. The simulation results show that in the Rayleigh Brillouin optical time-domain analysis system based on Simplex code, when the Rayleigh scattering optical power generated by the first order sideband of the pulse substrate is 0.5mW, the coding gain gradually increases with the increase of the coding length Large and tends to a stable value of 6.69 dB, the system’s optimal encoding length of 63 bit.