环形腔光纤激光器的理论和实验研究

【作者】 王海玲；

【导师】 张书敏；

【作者基本信息】 河北师范大学 ， 凝聚态物理， 2007， 硕士

【摘要】 随着光通信技术的不断发展,人们对光通信系统光源的要求越来越高,而光纤激光器以其显著的优势受到了广泛的关注,本文对环形腔掺Yb³⁺光纤激光器、环形腔掺Er³⁺光纤激光器和可调谐大功率光纤激光器进行了理论和实验研究,主要内容如下:1.在忽略放大自发辐射（ASE）的情况下,从速率方程出发,详细推导出环形腔掺Yb³⁺光纤激光器的阈值功率、增益、斜率效率及输出功率的解析表达式;对环形腔掺Yb³⁺光纤激光器进行数值模拟,详细分析了激光器阈值、输出功率、增益等重要参数与抽运功率、光纤长度、光纤掺杂浓度、激光器输出耦合比等参量之间的关系。结果表明,激光器结构参数的选择对激光器的优化设计具有重要意义。2.从偏振主态理论出发,分析了利用非线性偏振旋转技术实现光纤激光器波长可调谐的机理,并推导出光纤激光器的工作波长、调谐带宽、调谐精度等特性与光纤长度、偏振角等结构参数之间的关系。3.实验研制了以不同长度（10cm、20cm）的高掺杂浓度Yb³⁺纤为增益介质的短腔长光纤激光器,激光器的阈值功率为36.8mW和39.4mW、最大输出功率为21.1mW和12.7mW、斜率效率为8.2%和5.1%;利用光纤的非线性偏振旋转效应,实验研制了连续可调谐掺Yb³⁺光纤激光器,其连续调谐范围为9.88nm。4.理论分析了环形腔掺Er³⁺光纤环形腔激光器的输出特性,获得了稳态条件下激光器输出功率、阈值泵浦功率和斜率效率的解析表达式,结合MATLAB编程,对输出特性进行了数值模拟。5.基于非线性偏振旋转技术,采用功率放大器,实验研究了连续可调谐大功率掺Er³⁺光纤激光器。在放大器的泵浦功率为2.5W时,实现了在1546.96nm-1557.72nm波段波长连续可调谐的激光输出,激光器的边模抑制比高于30dBm,3dB谱线宽小于0.1nm,斜率效率高达80.1%。更多还原

【Abstract】 With the development of optical communication technology, lasers in the optical communication system have to meet the increasing requirement. Fiber lasers, as a device with distinguished advantage, have received great attention from the world. This thesis mainly describes the theoretical and experimental work on Yb³⁺-doped ring cavity fiber laser, Er³⁺-doped ring fiber cavity laser and tunable high power fiber laser. The main contents are shown as follows:1.By means of omitting the ASE and according to the rate equation,We deduced the expressions of threshold value, gain, slope efficiency and output power which belong to the Yb³⁺-doped ring cavity fiber lasers .The characteristics of the Yb³⁺-doped ring cavity fiber laser have been simulated. The relations between performance parameters which contain threshold power, output power and gain and structure parameters which consist of pump power, fiber length, impure chroma, output coupling rate of fiber laser have also been studied. The results show the choose of the structure parameters has important meaning to the optimized design of the laser.2. According to the PSP theory （principal state of polarization, PSP）, the mechamism of the tunable fiber laser using the nonlinear polarization technique（NPT） is researched. The relations between the output characters（such as the central wavelength,the tunable bandwidth and the tunable precision）and the parameters of the fiber laser（such as fiber length and polarization angle）are deduced.3.In experiment,we researched a short-cavity ring fiber laser with different fiber length（10cm and 20cm） has been designed and turned out with high concentration Yb³⁺-doped fiber as gain medium. The threshold power of the laser with gain fiber length 10cm is 36.8mW and the other is 39.4mW , and the maximum output power of the laser with gain fiber length 10cm is 21.1mW and the other is 12.7mW.The slope efficiency of the laser with gain fiber length 10cm is 8.2% and the other is 5.1%. Widely tunable ranges as 9.88nm is obtained.4. The output characteristics of Er³⁺-doped ring cavity fiber laser are theoretically studied. Under stationary conditions analytical expressions on output power, threshold pump power and slope efficiency are presented. After that, the output characteristics are simulated numerically combining MATLAB PROGRAMME.5. By means of nonlinear polarization rotation technique and using power amplifier, we studied a high power tunable Er³⁺-doped fiber laser. We achieved a lasing output with continuously tunable wavelength in the range from 1547.70 to 1557.52nm when the pump power of power amplifier is 1.5W and 2.5W. Its optical signal-to-noise ratio and 3-dB spectral width is about 30dBm and no more than 0.1 nm, and the slope efficiency is about 80.1%.更多还原