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基于布里渊散射的分布式光纤传感技术是目前国内外研究的热点之一,在基于布里渊光时域反射技术的分布式光纤传感技术中,以相干检测的传感精度最高,其关键是获得具有布里渊频移的参考光。详细分析了电光强度调制器(EOIM)的光波移频特性,实验研究了15 Gbit/s的铌酸锂波导电光强度调制器光波长1550 nm处11 GHz移频的实现;当微波调制频率及功率一定时,可方便地调节直流偏置电压来改变各阶光波的强度。设置直流偏置电压为6.5 V时,调制器总的输出光强最小,具有布里渊频移的一阶光波的相对光强最大,信噪比(SNR)最高,可用于分布式光纤传感中布里渊信号的相干检测。
Distributed optical fiber sensing technology based on Brillouin scattering is one of the hot spots at home and abroad. In the distributed optical fiber sensing technology based on Brillouin optical time-domain reflectometry, the sensing precision of coherent detection is the highest, The key is to get a reference beam with Brillouin frequency shift. The frequency shift characteristics of the electro-optic intensity modulator (EOIM) are analyzed in detail. The experiment of the 11 GHz frequency shift at 1550 nm in the 15 Gbit / s lithium niobate waveguide light intensity modulator is carried out. When the microwave modulation frequency and power A certain time, you can easily adjust the DC bias voltage to change the intensity of each order of light. When the DC bias voltage is set to 6.5 V, the total output light intensity of the modulator is the smallest. The first-order light waves with the Brillouin frequency shift have the largest relative light intensity and the highest signal-to-noise ratio (SNR), which can be used for distributed optical fiber sensing Coherent Detection of Brillouin Signals.