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宽带掺铒光纤放大器关键技术研究
Pivotal Techniques of Broadband Erbium-doped Fiber Amplifier(EDFA)
【作者】 王衍勇；
【导师】 李世忱；
【作者基本信息】 天津大学 ， 物理电子学， 2004， 博士
【摘要】 作为WDM系统的核心器件,掺铒光纤放大器(EDFA)的性能优劣直接影响了系统的传输带宽和距离。本论文围绕掺铒光纤放大器的关键技术所取得的主要研究成果如下:一、C波段和L波段EDFA的理论分析和优化设计及其实验基于铒离子能级速率方程和光传输方程,对掺铒光纤放大器的稳态放大特性进行了详细地理论分析。针对不同功能的C波段和L波段放大器,分别编写了相应的优化设计程序。根据数值模拟结果,分别完成了具有良好增益平坦度的C波段高增益(>31.5dB)、低噪声(<4.76dB)预放级放大器和L波段高增益(>38.84dB)、低噪声(<5.29dB)预放级放大器实验。二、C+L波段宽带EDFA的实现1.采用并联结构EDFA组合方案,实现了C+L波段的宽带放大,获得30dB以上57nm的3dB增益带宽。其中C波段25nm(1530nm～1555nm),L波段32nm(1570nm～1602nm)。2.国内首次进行了基于新型铋基掺铒光纤的宽带放大器和宽带荧光光源实验研究。在不同功率的信号输入情况下,该铋基掺铒光纤放大器都实现了1540nm～1610nm范围内的宽带放大。在基于此铋基掺铒光纤的超荧光光源实验中,我们利用双向泵浦、双通放大结构,得到了谱宽88nm、功率14.3dBm的宽带超荧光输出。三、EDFA增益平坦技术的理论研究和实现基于光纤环形镜的滤波原理分析,提出利用级联结构光纤环形镜实现EDFA增益平坦滤波的方案,并进行了相关实验研究。实验结果显示,使用级联FLM取得了明显的平坦效果,其1535nm～1557nm波长范围内的增益不平坦度由±5dB减小到±1dB。四、EDFA动态增益箝制技术的理论研究与实验1.使用数值模拟的方法对全光增益箝制EDFA的稳态特性和瞬态特性进行了全面地理论分析。研究了瞬态过程中系统参量(泵浦功率、环路损耗、上下载速度、上下载信道功率、箝制激光振荡波长等)对剩余信道驰豫振荡特性的影响。2.首次提出了使用光纤环形镜实现双波长增益箝制的方案,并得以成功的实现。实验结果显示:放大器处于增益箝制状态时,其输出增益波动最小可达0.1dB。
【Abstract】 As the key device of WDM system, the behavior of erbium-dopedfiber amplifier(EDFA) will directly influence the transmissionbandwidth and distance of the system. In this dissertation some pivotaltechniques of EDFA were investigate and experimentally studied withthe productions as follows:1. Theoretical analysis and optimization of C band and L band EDFAand experimentsBased on the rate-equations and propagation equations, the stable stateoutput property of EDFA was fully studied using self-made computerprograms. With these programs EDFA of different functions weredesigned and optimized. High gain low noise figure C band and L bandpreamplifier have been realized in our experiments with the G>31.5dB,NF <4.76dB and G>38.84dB,NF<5.29dB respectively.2.Experiment on the C+L band broadband EDFA1) With the C and L band EDFA combined in parallel connection scheme,broadband gain above 30dB were achieved with the 3dB gain bandwidthof 57nm which including 25nm(1530nm～1555nm)in C band and32nm(1570nm～1602nm) in L band.2)We give the first report on the experimental studies of bismuth-basederbium-doped fiber amplifier and broadband super-fluorescentsource(SFS) . This new type EDFA proved its ability of broadbandamplification in 1540nm~1610nm range under different inputconditions . And the bidirectional-pump, double-pass structure SFSbased on this novel type erbium-doped fiber demonstrated the 88nmline-width with the output power of 14.3dBm.3. Study on gain flatten techniques and experimentsBased on the investigation of the fiber loop mirror(FLM), ancascade-FLM filter was proposed and realized to flatten the gain of Cband EDFA. With this filter the gain fluctuation was reduced to ±1dBfrom ±5dB in the range of 1535nm～1557nm .4.Theoretical analysis of optical auto gain clamping(OAGC) EDFA andexperiments1) Theoretical investigated the stable and transient property ofOAGC-EDFA using computer simulation. The influence to the residualchannels induced by the variation of pump power, loop loss, add/droppower, clamping wavelength were fully considered.2) We proposed the scheme for the first time to use the FLM in thefeedback loop as filter to realized the dual-clamping EDFA. The 0.1dBgain ripple of the dual-wavelength-clamping EDFA proved the validityof this scheme.