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基于外光注入VCSELs单周期振荡的毫米波产生及其在ROF系统中的应用
Optical Millimeter-wave Generation Based on Periodone Oscillation in VCSELs Subject to Optical Injection and Its Application in ROF System
【作者】 冷宗敏；
【导师】 吴正茂；
【作者基本信息】 西南大学 ， 光学， 2010， 硕士
【摘要】 随着人类社会全球信息化的进程,人们对高速多媒体通信带宽的需求不断提高,毫米波频段的应用逐步进入人们的视野。频率比微波更高的毫米波有着宽频带,大容量传输信号的优势,但是容易受到大气环境的影响而产生衰减,难以实现远距离传输目标。将毫米波和光纤传输技术相结合,可以有效解决毫米波传输距离短等问题,这就是光纤无线通信(ROF)系统。光纤拥有丰富的频带资源和抗电磁干扰能力,毫米波可以使无线通信向更大容量和更高速率迈进,二者结合的ROF技术具有无限的发展前景。目前,毫米波产生的主要方法有：直接调制技术,上下变频技术,光外差技术和电吸收收发器技术。本文提出一种基于外光注入垂直腔表面发射半导体激光器(VCSELs)单周期振荡的毫米波产生方案。利用自旋反转理论模型(SFM),对外光注入下VCSELs的动态行为进行了研究,着重讨论VCSELs处于单周期振荡时所产生的毫米波的性能。研究表明：在适当的参数条件下,主VCSELs的输出注入到副VCSELs,可使副VCSELs处于单周期振荡,其输出的光谱中只含有两个主频率,即第一边带与中心载波频率成分,经过拍频可获得毫米波；通过调节注入光强度以及主副VCSELs的失谐频率,可以得到频率范围极广的毫米波。同时,本文还分析了采用上述方法产生的毫米波在ROF系统中的传输特性。由于此时产生的毫米波具有单边带(SSB)调制特性,因此能够较好地抑制光纤色散的影响,进而可改善ROF系统的传输性能。
【Abstract】 With the coming of information age, the demand of broadband multimedia services is going up quickly and at the same time, the application of millimeter-wave attracted much more attentions. The millimeter-wave with higher frequency has the advantages of broad band and large capacity, but in the air, millimeter-wave cannot transmit over a long distance due to large attenuation. Therefore, a new technology of radio over fiber (ROF), which integrates millimeter-wave wireless transmission and fiber wired transmission, has attracted considerable interests for such ROF systems are capable of realizing long distance transmission of millimeter-wave signals. Optical fiber has rich frequency bandwidth and the ability of anti-electromagnetic interference, while millimeter-wave can make wireless communication realize the larger capacity and the higher rate. The combination of them has promising prospects for communication development. At present, the methods of millimeter-wave generation include direct modulation, up and down frequency conversion, optical heterodyne and electro-absorption transceiver technology.In this paper, a novel method to generate millimeter-wave based on period-one oscillation in a slave VCSEL subject to optical injection from a master VCSEL is proposed. Based on spin-flip model (SFM), the dynamic behaviors of VCSELs subject to optical injection and millimeter-wave generated by VCSELs based on period-one oscillation have been researched. The results show that, through selecting proper system parameters, the slave VCSEL can be oscillate at period-one state with a dual-frequency optical spectrum distribution, then a low phase-noise millimeter-wave beat signal can be obtained by a high-speed photodiode. Through adjusting the injected strength and the frequency detuning between the slave and master VCSELs, optical millimeter-wave with different frequency can be obtained. Meantime, the transmission characteristics of millimeter-wave generated by above method in ROF system have also been researched. The influence of the fiber dispersion can be suppressed due to the generated millimeter-wave with single sideband (SSB) modulation performance, and the transmission performance of ROF system can be significantly improved.