【作者】 刘胜芳；

【导师】 吴正茂；

【作者基本信息】 西南大学 ， 光学， 2008， 硕士

【摘要】 垂直腔面发射激光器(VCSEL)是一种新型的半导体激光器,较传统的边发射激光器来说具有低阈值、单纵模工作、发散角小、动态调制频率高、易实现二维集成等优点,在光通信,光互联,图像信号处理等方面有着重要的应用前景。近年来混沌保密通信得到了广泛的应用。由于光混沌的动力学行为复杂,对参数相当敏感,因此成为保密通信的一个热点。在混沌通信中,传输速率是最重要的指标之一,由混沌载波基频决定。混沌载波频率与激光器的弛豫振荡频率密切相关,弛豫振荡频率限制了半导体激光器的最大调制频率,最近,通过强光注入到VCSEL,实验上已获得50GHz的调制带宽,因此可以预计,外部光注入可以使外光反馈VCSEL输出的混沌载波基频得到很大的提高。基于此本文研究了外部光注入对VCSEL带光反馈的VCSEL输出混沌载波基频的影响。研究结果表明,在注入锁定区域内,当外部注入光频率与VCSEL自由运行的振荡频率失谐一定时,随着外部光注入强度的增加,混沌载波基频总体呈现上升的趋势,在增加的过程中伴随着波动;同时失谐频率对混沌载波基频也有重大影响,在正失谐时,混沌载波基频随着失谐频率的增加而增大,通过调整失谐频率和注入强度大小,外部光注入可以使混沌载波基频得到大幅度的提高;当归一化的注入系数K=330,失谐频率为42GHz,可得到基频位于47.3GHz的混沌信号输出。众所周知,混沌载波基频决定着最大的混沌传输速率,所以本文的研究对提高混沌传输速率具有很高的价值。更多还原

【Abstract】 As a new kind of semiconductor laser, vertical-cavity surface-emitting lasers(VCSEL) have such merits as low threshold, single longitudinal mode operation, small angle of divergence, high dynamic modulating frequency, easily implemented two-dimension integration which makes VCSEL have significant implication prospects in optical communication, optical interconnection, image signal processing, etc. As a result, the researches on VCSEL have been paid special attentionRecently, Chaos private communication has get an extensive application, optical chaos become a hot topic of private communication for a fundamental phenomenon of nonlinear dynamics and highly sensitivity to the parameters, the rate of transmission is one of the most important Index sign in chaotic communication which is determined by the chaotic carrier fundamental frequency. Carrier frequency is closely related to the relaxation oscillation frequency, and the relaxation oscillation frequency is considered to be the characteristic frequency that defines the maximum modulation frequency of a semiconductor. At present, the experiments focused on the VCSELs, where a relaxation oscillation frequency 50GHZ was achieved, therefore we can anticipate, the chaotic carrier fundamental frequency of VCSEL’s output with optical feedback can be enhanced by using the external optical injection technique.In this paper, the influences of the external light injection on the chaotic carrier fundamental frequency of VCSEL with optical feedback have been investigated. The results show that in the injection locking area, for the fixed frequency offset between the master laser diode and the slave VCSEL, the chaotic carrier fundamental frequency will be increased generally with the increase of injected strength, accompany with motion in the process of increase; Simultaneously, the frequency offset have the important influence to the chaotic carrier fundamental frequency, when the frequency offset is positive, the chaotic carrier fundamental frequency also increased generally with the increase of the frequency offset, chaotic carrier fundamental frequency can be improved significantly by adjusting frequency offset and injected strength. For the normalized injected strength K is 330 and frequency offset is 42GHz, chaotic output with 47.3GHz fundamental frequency can be obtained. Therefore, the investigation in this paper has the high research value for improving the transmission rates.更多还原