基于实测布里渊(Brillouin)增益谱确定了合适目标函数。数值产生了大量的布里渊增益谱, 利用这些谱信号系统研究了信噪比、扫频间隔、扫频点数、扫频范围和谱特征参数g0、vB、ΔvB的取值对布里渊增益谱特征参数提取准确性的影响规律。结果表明: 特征参数提取误差随信噪比增加成指数规律下降, 随扫频点数增加(或扫频间隔减少)而下降; vB的提取误差随ΔvB的增加而线性增大, ΔvB的值对其他参数的提取准确性几乎无影响; 扫频点数固定时扫频范围选择太大或太小时的误差均较大, 实际应该选择2ΔvB左右。研究结果对基于布里渊散射的传感时相关参数选择具有参考价值。

Based on the measured Brillouin gain spectrum, the suitable objective function was chosen. According to a large number of numerically generated Brillouin gain spectra, the influences of signal-to-noise ratio(SNR), scanned frequency interval, number of scanned frequency, frequency scanning range, spectra key parameters g0, vB and ΔvB on the accuracy in the parameters extracted from Brillouin gain spectrum were systematically investigated. The results indicate that the errors in the extracted parameters exponentially decrease with increasing SNR. The errors in the extracted parameters decrease with increasing number of scanned frequency or decreasing scanned frequency interval. The error in the extracted vB increases proportionally with ΔvB. However, ΔvB has no influence on the accuracy in the extracted g0 and ΔvB. If the number of scanned frequency remains constant, then too wide or narrow frequency scanning range will results in significant errors. The optimal frequency scanning range is close to 2ΔvB. This work provides a frame of reference in which you can determine the suitable parameters in Brillouin scattering-based sensing.