共查询到17条相似文献,搜索用时 124 毫秒
1.
利用双光反馈垂直腔面发射半导体激光器(VCSELs) 两个正交偏振模式输出的两个混沌信号作为混沌载波, 构建了一个双信道的混沌保密通信系统, 并对该系统的通信性能进行了数值仿真研究.研究结果表明: 通过合理的选取反馈参量, 双光反馈VCSELs两个偏振模式输出的混沌信号能很好地隐藏外腔反馈延时特性; 双光反馈VCSEL两个偏振模式输出的混沌信号通过偏振保持注入到接收VCSEL中, 在强注入锁定条件下可以实现很好的混沌同步, 同步性能对频率失谐的容忍性随着注入强度的增加而加强; 在附加混沌调制加密方式下, 500 Mbit/s的信号在传输过程中能够得到很好的隐藏, 同时在接收端可以成功解调; 随着通信速率的增加, Q因子呈现下降的趋势, 但对于 6 Gbit/s的信息, Q因子仍大于6.
关键词:
垂直腔面发射激光器
双光反馈
双信道
混沌通信 相似文献
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研究了外部光注入对光反馈垂直腔表面发射半导体激光器(VCSEL)混沌载波基频的影响.研究结果表明: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;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42 GHz,可得到基频位于47.3 GHz的混沌信号输出.
关键词:
VCSEL
光注入
光反馈
混沌载波基频 相似文献
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在一个双光反馈半导体激光混沌系统中,固定其中一个反馈腔镜(固定腔M1)的反馈延迟时间以及反馈强度,实验研究了另一个反馈腔镜(可变腔M2)的反馈延迟时间以及反馈强度对系统混沌输出的延时反馈特征的影响.研究结果表明:在可变腔M2与固定腔M1的反馈强度相等的条件下,改变M2的腔长,当其腔长约等于(但不能严格等于)M1的腔长或者腔长的一半时,系统将呈现较好地抑制延时反馈特征效果;当M
关键词:
半导体激光器
双光反馈
混沌输出
延时特征 相似文献
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在混沌通信系统中,混沌载波的时延特征直接影响着通信系统的安全性,因此隐藏混沌载波的时延特征信息十分重要。本文基于外腔反馈式半导体激光器(ECSL)的单光注入结构,引入激光器参数失配,详细阐述了一种通过主从激光器参数失配来消除混沌信号时延特征的方法。利用自相关函数作为量化工具,对混沌信号的时延隐藏效果进行量化分析,数值研究了主从激光器间的参数失配对混沌信号时延消除的影响,并结合注入强度与频率失谐开展了进一步综合研究。研究结果表明:引入激光器参数失配对时延隐藏的效果影响显著,参数失配率在-0.4~0范围时有助于在从激光器混沌输出中隐藏主激光器外腔引入的反馈时延;而且,当主激光器注入强度在10ns-1~20ns-1范围内,主从激光器频率失谐控制在-20GHz附近时,信号时延隐藏效果最佳。因此,由此单混沌光注入系统产生的混沌信号可显著提高混沌载波的安全性,进而增强其潜在应用的性能。 相似文献
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外光反馈下的半导体激光器可视为混沌载波发射机.数值研究发现,外部强光注入可以显著提高混沌载波发射机的带宽,带宽提高的程度在一定范围内与注入光的强度成正比.当外部光注入系数kinj=0.39时,混沌载波的带宽由无光注入时的2.7GHz增大到14.5GHz,提高了5倍多.研究还发现,在相同的注入强度条件下,当注入光的频率比半导体激光器的中心频率高2—4GHz时,可实现最大限度的带宽增强.此外,适当提高半导体激光器的偏置电流也可以在一定程度上提高其产生的混沌载波的带宽.
关键词:
半导体激光器
混沌
带宽 相似文献
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实验利用双反馈半导体激光器获得了关联维数为3.8的高维混沌光.同时对比分析了双反馈与单反馈两种不同模式产生混沌的区别.结果表明:在反馈强度均为-26 dB时,双反馈产生混沌的关联维数高于单反馈产生混沌的关联维数2.6;双反馈可获得带宽为11 GHz的混沌光,为单反馈产生混沌带宽5.5 GHz的两倍.当双反馈的两个外腔长度不相等时,混沌的自相关曲线能很好的隐藏外腔长度信息,可提高混沌通信的保密性.
关键词:
双反馈
半导体激光器
混沌
带宽 相似文献
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Bandwidth-enhanced chaos synchronization in strongly injection-locked semiconductor lasers with optical feedback is numerically studied based on laser rate equations. The bandwidth of the chaotic carrier frequency in a semiconductor laser with optical feedback is expanded roughly three times by strong optical injection compared with the bandwidth when there is no optical injection. Using a bandwidth-enhanced semiconductor laser as a chaotic transmitter and receiver, we synchronized transmitter and the receiver lasers in a complete chaos synchronization scheme. 相似文献
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The message filtering characteristics of the receiver in closed-loop chaotic optical communication system are numerically studied based on laser rate equations. A pair of external cavity semiconductor lasers was employed as the chaotic carrier transmitter and the synchronized chaos receiver. We examined the filtering properties of the semiconductor laser receiver for message encoded with chaos masking. Our results demonstrate that, the lower the message frequency, the more easily the receiver filters out the message from chaotic carrier. We also analyzed the effects of each parameter mismatches between the transmitter and the receiver on the quality of the recovered message. Comparing the synchronization quality with the signal-to-noise ratio affected by parameter mismatches, we find that the quality of the recovered message depends not only on the synchronization quality but also on the filtering characteristics of the receiver. The filtering characteristics of receiver will be playing an important role on the quality of the recovered message in the case of large mismatches. 相似文献
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利用光纤环长外腔光反馈半导体激光器产生了频谱平坦的宽带混沌激光,其对应的激光频谱可有效地隐藏外腔的谐振频率,增加了系统的保密性.通过单向耦合方式,将产生的混沌激光注入到另一个参数相近的半导体激光器中,实现了平坦宽带混沌同步输出,两同步激光器输出的相关系数达到084.同时实验研究了注入强度和主从激光器的频率失谐对同步质量的影响,结果表明在强光注入锁定下,在很大频率失谐范围内均可实现同步,而且注入强度越大,主从激光器输出的相关系数越大,维持混沌同步所允许的频率失谐范围越大.
关键词:
混沌同步
单向光纤环
光反馈
半导体激光器 相似文献
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非相干光反馈与非相干光注入混沌同步通信系统仿真分析 总被引:1,自引:0,他引:1
本文对非相干光反馈与非相干光注入激光混沌同步保密通信系统进行了理论仿真研究.本系统为Pecora-Carroll混沌同步系统,基于Lang-Kobayashi速率方程,建立了发送激光器和接收激光器的理论模型.利用该模型分析了同步建立时间、同步误差,混沌键控编码/解码以及调制速率等特性.仿真结果表明系统具有很好的同步性能和保密性,混沌同步时间约为1 ns,混沌键控编码速率可达1 Gbit/s.研究结果对非相干光反馈与非相干光注入激光混沌同步保密通信系统的设计具有重要参考价值. 相似文献
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Chaotic on off keying for secure communications 总被引:4,自引:0,他引:4
We experimentally demonstrate a chaotic on-off keying method for secure communications by using chaos synchronization in two microchip lasers. The output of the microchip laser in the transmitter is externally modulated with an acousto-optic modulator at ~4 MHz . One encodes a digital message in the chaotic carrier by turning the modulation on and off at 100 kHz. Because the accuracy of synchronization for the slave laser in the receiver tends to be degraded in the presence of external modulation in the injection laser signal, one can distinguish two binary states. The digital message can be recovered as an envelope of the chaotic oscillation when the difference between the two laser outputs of the transmitter and the receiver is calculated. 相似文献
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In this paper, a novel chaotic relay system, based on cascaded synchronization in optoelectronic negative feedback chaotic semiconductor lasers, is presented. Synchronization characteristics and the influence of parameter mismatches on synchronization performances are investigated. The results show that the complete synchronization can be achieved under suitable system parameters; internal parameter mismatches of the lasers have influence on synchronization quality, but the system possesses more robustness to parameter mismatches compared with cascaded synchronization based on coherent optical feedback. Moreover, communication related issues are also investigated. Under the additive chaos modulation (ACM) encryption scheme, encoded messages can be successfully extracted at both mediator laser (ML) and receiver laser (RL) parts; parameter mismatches of the lasers will affect messages decoding, but the influence is not strong. 相似文献
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Experimental observation of both anticipated and retarded synchronization is demonstrated using unidirectionally coupled semiconductor lasers with delayed optoelectronic feedback. Depending on the difference between the transmission time and the feedback delay time, the lasers fall into either the anticipated or the retarded synchronization regime, where the driven receiver laser leads or lags behind the driving transmitter laser. The two regimes are observed to have the same stability of chaos synchronization in the presence of small perturbations by noise and parameter mismatches. In both regimes the observed time shift between the synchronized chaotic waveforms is found to be equal to the difference between the transmission time and the feedback delay time. 相似文献