基于喇曼组合放大的长距离光纤传输系统

【作者】 李立；

【导师】 饶云江；

【作者基本信息】 电子科技大学 ， 光学工程， 2009， 硕士

【摘要】 近年来,由于具有与光纤系统完全匹配的独特优点,光纤激光器可以方便地应用于各种光纤通信和光纤传感系统,光纤激光器技术在高速率大容量波分复用光纤通信系统、高精度光纤传感技术和大功率激光等方面呈现出广阔的应用前景和巨大的技术优势,受到了来自电子信息、工业加工和国防科技等领域的高度关注。本文研究了基于喇曼组合放大的带光纤光栅光纤喇曼激光器长距离传输系统,从理论和实验两方面分析了此系统在光纤通信中的应用。具体完成的工作如下。首先,总结了光纤中的非线性效应对光纤通信的影响及其在光纤通信中的应用,研究了光纤中受激布里渊散射的阈值特性,并进行了两种G.652B和一种G.652D单模光纤的受激布里渊散射的阈值的测量实验,从理论上分析了光纤SBS阈值估算公式,理论估算值与实验测量值吻合很好。然后,从喇曼散射的原理出发,对喇曼放大的原理及其应用进行了分析,提出了基于喇曼组合放大的带光纤光栅喇曼激光器光纤长距离传输系统,即利用两级泵浦光产生的喇曼效应,对信号光进行喇曼组合放大,也就是在光纤光栅对形成的谐振腔产生的激射光对信号光进行喇曼放大的基础上,利用抽运泵浦光再对信号光进行喇曼放大,比仅依靠激射光的喇曼放大可以获得更高的喇曼增益以实现长距离的带增益钳制的光纤传输,建立了此系统的理论模型,并采用开关增益法进行了光纤喇曼增益系数的测量实验。最后,分析了喇曼放大器的性能参数,实验搭建了基于喇曼组合放大的长距离光纤传输系统,测量了该系统的开关增益、自发辐射噪声、噪声指数和在光纤长度上的光功率分布等,实现了国际上已报道的此类系统的最长准无损光纤传输距离(125km)。对系统的增益、自发辐射噪声及光功率分布实验结果与理论模拟进行了对比,并通过系统的理论模型分析了泵浦方式、光纤长度对系统的增益钳制效果、噪声性能和非线性损伤的影响。结果表明该系统作为一个长距离光纤传输系统,其增益钳制效果对克服密集波分复用系统中信号的失真和通道串扰的影响有着很好的应用前景。更多还原

【Abstract】 In recent years, because of being perfectly matched with the optical fiber system, fiber lasers can be conveniently applied to a variety of fiber-optic communications and optical fiber sensing systems. The broad application prospects and enormous technological advantages of the fiber laser technology have shown in the high-speed large-capacity WDM optical fiber communication systems, high-precision optical sensor technology and high-power laser, etc. which have attracted attention from the research and development technology from the field of electronic, industrial processing and national defense science. In this paper, the long-distance transmission system of Raman fiber laser with FBG based on the Raman hybrid amplification has been studied, and its applications in optical fiber communication have been analyzed from both theoretical and experimental. The main work can be summarized as follows:Firstly, the nonlinear effect and applications in optical fiber communications have been summarized; the characteristics of Stimulated Brillouin Scattering (SBS) threshold have been studied. The SBS thresholds of the single mode fiber of two G.652B and one G.652D are measured, the estimation formula of the SBS threshold in optical fiber has been analyzed theoretically, and the theoretical estimates and experimental measurements are in good agreement.Secondly, the principle of the Raman amplification and its application are analyzed from the theory of Raman scattering. The long-distance transmission system of Raman fiber laser with FBGs based on the Raman hybrid amplification has been constituted, which is by the use of Raman Effect generated by two pumps, and the signal light is amplified on Raman hybrid amplification. By using fiber Bragg grating to structure resonant cavity, the lasing light is generated as a secondary pump for the secondary Raman amplification to the signal light, to obtain a higher Raman gain to achieve long-distance optical fiber transmission with no loss of gain-clamped. A theoretical model of this system has been set up. The measurement experiment of the fiber Raman gain coefficient has been carried out by gain switching method. The measuring principle has been analyzed, and the experimental data and the literature value have been compared.Finally, the Raman amplifier performance parameters are analyzed. The experiment of the long-distance transmission systems of Raman fiber laser with FBGs based on the Raman hybrid amplification has been built Experimently. The system’s switching gain, ASE noise, noise figure and the signal power’s distribution have been measured, and the longest non-loss optical fiber transmission distance (125km) to the best of our knowledge has been achieved.The effects of gain-clamped from the theoretical model system have been studied, and the effects of the way pumped and the fiber length in the dynamic range, noise performance and the impact of non-linear damage are mainly discussed. The results show that the system as an ultra-long fiber transmission system, the effects of gain-clamped in DWDM system to overcome the signal distortion and channel crosstalk has a very good application prospects.更多还原