瑞利布里渊光时域分析系统中电光调制器的理论模型与实验研究

瑞利布里渊光时域分析系统能够以非破坏性方式实现单光源、单端工作,利用强度型电光调制器同时调制脉冲基底和脉冲信号是获得该系统所需连续光和脉冲光的关键技术.本文理论分析、仿真和实验研究了一种将脉冲信号输入到电光调制器偏置端、微波信号输入到电光调制器射频端同时调制脉冲基底和脉冲信号的新调制方法,探讨了电光调制器用于瑞利布里渊光时域分析系统时的最佳工作点问题.结果表明,当调制脉冲基底和脉冲时分别将电光调制器偏置在传输曲线的谷点和峰点,并根据实际系统的组成和性能指标要求选择合适的微波调制信号幅度,可获得满足瑞利布里渊光时域分析系统要求的连续光和脉冲光.本文的研究结果为瑞利布里渊光时域分析系统的最佳化设计提供了理论依据.

Theoretical Model and Experimental Study of Electro-optic Modulator in Rayleigh BOTDA System

Rayleigh Brillouin optical time domain analysis system can be operated with single laser and single end of sensing fiber in a non-destructive way, and the modulation of pulse base and pulse with an intensity-type electro-optic modulator is the key technique for obtaining continuous light and pulse light required by the system. A new modulation method with a pulse applied to the bias port of electro-optic modulator and a microwave applied to the RF port of the electro-optic modulator to modulate the pulse base and pulse is analyzed theoretically, simulated with computer and studied experimentally in this paper, and the optimal operating point of electro-optic modulator in Rayleigh Brillouin optical time domain analysis system is discussed. The results show that if the operating point of electro-optic modulator is set at the valley and peak of its transmission curve respectively and the amplitude of microwave modulation signal is chosen appropriately according to the configuration and performance of the actual system, then the continuous light and pulse light meeting the requirements of Rayleigh Brillouin optical time domain analysis system can be obtained when the pulse base and pulse are to be modulated. The results of this study can provide a theoretical basis for the optimal design of Rayleigh Brillouin optical time domain analysis system.