【作者】 黄嘉福；

【导师】 许惠英；

【作者基本信息】 厦门大学 ， 无线电物理， 2008， 硕士

【摘要】 随着全球通信业务快速增长,对新一代的光纤通信系统的容量提出了越来越高的要求。从而,也相应地对现代光通信系统的核心部件——光放大器提出更高的挑战。目前,新一代光放大器——拉曼光纤放大器（RFA）被认为最具潜力和发展前景。其中首要问题是寻找合适的拉曼光放大器泵浦源。光纤激光器作为第三代激光器,与传统激光器相比具有许多优点,在许多方面己体现出具备理想泵浦源的优势。特别是拉曼光纤激光器（RFL）因其同时具有高功率输出及激射波长灵活可调的特性,能弥补目前半导体激光器的不足,而成为光通信系统中的理想泵浦源。本论文基于光纤中受激拉曼散射（SRS）现象的基本原理,围绕拉曼光纤激光器及多波长拉曼光纤激光器（MRFL）展开研究。首先,概述了SRS的基本原理,并对级联拉曼光纤激光器进行了理论分析。给出了拉曼光纤激光器的理论模型,通过对模型的分析给出了基于Newton-Raphson法的数值求解方法。同时为了提高运算速度及保证稳定性,我们采用拉曼光纤激光器动力学方程的近似解析解作为数值算法的初始值。结果表明,采用这种改进的数值算法可以有效提高运算速度和稳定性。其次,分别对Nd:YVO₄固体激光器泵浦和掺镱双包层光纤激光器（DCFL）泵浦的RFL进行实验研究。其中用Nd:YVO₄固体激光器泵浦的RFL获得了1.15W的1484nm拉曼激光输出,并且其功率波动在一小时内小于6%;采用DCFL泵浦RFL,获得了3.44W的1484nm拉曼激光输出,光-光转换效率为28.1%。实验结果都达到预期效果,并与理论基本一致。最后,在此基础上,我们结合保偏光纤Sagnac环梳状滤波功能及综合利用掺磷光纤中P₂O₅和SiO₂的拉曼频移,第一次成功地应用掺磷光纤的拉曼频移效应实现了O波段波长间隔可调谐的多波长拉曼光纤激光器。在1064nm的泵浦功率为2.5W情况下,分别实现波长间隔为0.8nm和0.43nm的多波长激光稳定输出,实验结果与理论分析一致。更多还原

【Abstract】 With the rapid development of global communications, the ultra-high capacity of a new generation optical fiber communications system is demanded urgently. Therefore, as one of the vital components of optical communication systems, optical amplifiers are encountering a great challenge. Especially, Raman fiber amplifier （RFA） as a new generation amplifier has been thought as an ideal and potential solution. However, a key problem is that a suitable Raman pump source is very difficultly found. As a third-generation laser, fiber lasers are an excellent candidate as a Raman pump source, due to their advantages compared with conventional laser. Especially, because Raman fiber lasers （RFL） can be high-power output and the flexible lasing wavelength, they can perfectly meet the requirements of Raman pump sources and can replace the conventional diode laser.Based on the principle of stimulated Raman scattering （SRS） in single-mode fiber, the dissertation is focused on the study of RFL and multi-wavelength Raman fiber laser （MRFL）.Firstly, the basic theory of SRS is introduced in details. The dynamics coupling equations governed the RFL are given and a Newton-Raphson-based shooting method is proposed to numerically solve it. In order to improve the efficiency and stability of the algorithm, the approximation solution of the coupling equations is used as an initially guessing value for the algorithm. It is shown that the computation time and stability can be significantly improved based on the improved algorithm.Secondly, the experiments of RFL pumped by the Nd: YVO₄ solid-state laser and double clad fiber laser （DCFL） are investigated, respectively. We obtain the output power of 1.15W/1484nm and the power fluctuation less than 6% in one hour pumped with a Nd:YVO₄ solid state laser. Furthermore, a higher output power of around 3.44W is also obtained when a DCFL is used as the Raman pump source. The optical conversion efficiency is about 28.1%. All experimental results are good agreement on the theoretical those.Finally, by use SRS of both P₂O₅ and SiO₂ in the P-doped fiber, it is the first time that a stable and spacing-adjustable phosphsilcate multi-wavelength Raman fiber in the O-band is achieved successfully. With the pump power of 2.5W, the multi-wavelength oscillations spaced at 0.8nm and 0.43nm have been observed, respectively.更多还原