双滤波反馈半导体激光器获取低延时特征的混沌信号研究

发布时间：2018-07-13 12:58

【摘要】：基于外部扰动下半导体激光器输出的混沌信号因在混沌保密通信、高速随机数获取、混沌雷达等方面巨大的应用价值而受到越来越多的关注。在众多的混沌激光产生方式中,光反馈半导体激光器因具有结构简单、容易操作、容易获得高维混沌激光等优点而备受欢迎。然而,光反馈半导体激光器输出的混沌信号中不可避免的具有时延特征,从而极大的阻碍了光反馈半导体激光器在相关领域的应用,如降低保密通信系统的安全性、降低随机数的统计性能、降低混沌雷达的测量精度精度。因此,研究光反馈半导体激光器混沌输出的延时特征抑制的相关理论和技术具有重要的现实意义。通常,光反馈半导体激光器的外腔大多采用平面镜,研究表明利用诸如法布里-珀罗干涉仪或光纤布拉格光栅这样的具有色散特性的滤波器来替代平面镜,可以更好的抑制系统输出延时特征的效果。基于此,本文利用两个法布里-珀罗干涉仪替代双光反馈半导体激光器中的平面镜,构成双滤波反馈半导体激光器系统,并理论分析了反馈强度、反馈时间、滤波器带宽和半导体激光器中心频率和滤波器中心频率的频率失谐等参量对系统输出混沌信号的延时特征的影响。研究结果表明:当双滤波反馈系统的反馈时间大致为半导体激光器弛豫振荡周期的二分之一的时候,激光器输出混沌信号的时延特征可能被很好的抑制;对于2?为2.92ns和3.08ns的情况,通过适当选取两个反馈腔的反馈强度,系统混沌输出延时特征的抑制效果可以得到进一步提高。此外,通过分析滤波器带宽以及半导体激光器中心频率对滤波器中心频率的失谐对延时特征抑制的影响,为了确定取得满意的低延时特征混沌信号需要的反馈参数的范围,在频率失谐与滤波带宽构成的参数空间绘制了延时特征的分布图。
[Abstract]:The chaotic signal output from semiconductor laser based on external disturbance has attracted more and more attention because of its great application value in chaotic secure communication, high-speed random number acquisition, chaotic radar and so on. Among the many chaotic laser generation methods, optical feedback semiconductor lasers are popular because of their simple structure, easy operation and easy access to high-dimensional chaotic lasers. However, the chaotic signal output by optical feedback semiconductor laser inevitably has the characteristic of delay, which greatly hinders the application of optical feedback semiconductor laser in related fields, such as reducing the security of secure communication system. The statistical performance of random numbers is reduced and the measurement accuracy of chaotic radar is reduced. Therefore, it is of great practical significance to study the delay characteristic suppression of optical feedback semiconductor lasers. Generally speaking, the external cavity of optical feedback semiconductor laser is mostly planar mirror. It has been shown that a dispersive filter such as Fabry-Perot interferometer or fiber Bragg grating is used to replace the planar mirror. Can better suppress the system output delay characteristics of the effect. Based on this, this paper uses two Fabry-Perot interferometers to replace the planar mirror in the double-optical feedback semiconductor laser, and constructs a double-filter feedback semiconductor laser system. The feedback intensity and feedback time are analyzed theoretically. The effects of the filter bandwidth and the frequency detuning of the semiconductor laser and the central frequency of the filter on the delay characteristics of the chaotic signal output from the system. The results show that when the feedback time of the double filter feedback system is approximately 1/2 of the relaxation oscillation period of the semiconductor laser, the delay characteristics of the laser output chaotic signal may be well suppressed. In the case of 2.92ns and 3.08ns, the suppression effect of chaotic output delay characteristics can be further improved by properly selecting the feedback intensity of two feedback cavities. In addition, by analyzing the influence of filter bandwidth and central frequency of semiconductor laser on delay characteristic suppression, the range of feedback parameters needed to obtain satisfactory chaotic signals with low delay characteristics is determined. The distribution of delay characteristics is plotted in the parameter space of frequency detuning and filter bandwidth.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248.4

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