基于双折射滤波效应的可调谐多波长掺铒光纤激光器的研究

发布时间：2018-04-04 10:03

本文选题：掺铒光纤激光器　切入点：多波长　出处：《哈尔滨工业大学》2015年硕士论文

【摘要】：由于在高容量光纤通信、光学检测以及光纤传感等领域中的广泛运用,近年来可调谐多波长掺铒光纤激光器受到了研究者们的广泛关注。然而,现有的可调谐多波长掺铒光纤激光器通常借助梳状滤波器的调谐性能来实现自身的调谐功能,存在调谐功能单一、多个参量控制交叉串扰和激光调谐可控性差等问题。为克服以上问题,本文提出了一种新型的可调谐多波长激光器,具备多个参量单独调谐的功能。此外本文还分别从理论和实验方面对多波长掺铒光纤激光器的调谐性能进行研究,提出了可调谐激光器输出特性的优化方案,具体研究内容如下:首先,利用双折射滤波效应的调谐性能,本文提出了一种具有环路结构的Lyot双折射滤波器理论模型,利用琼斯矩阵法分别对一阶和二阶Lyot双折射滤波器的输出特性进行了研究,并进行了数值仿真验证。其次,本文提出并证明了一种新型的可调谐多波长激光器。其调谐功能是通过将功率对称型非线性光纤环镜引起的强度相干损耗效应与一阶Lyot双折射光纤滤波器引起的双折射滤波效应相结合而实现。利用非线性光纤环镜与Lyot双折射滤波器在调谐功能上的互补性,实现了多输出参量的单独调谐。通过调节一阶Lyot滤波器,能实现波峰位置在一个自由光谱区内连续的精细调谐。而调节NOLM可实现光谱范围的粗调谐功能,光谱最大移动量达到8 nm。同时,本文分别采用调节NOLM输入光偏振态和控制泵浦功率两种方式实现对波长数目的控制,最大波长数目高达18条。此系统具有较好的稳定性,波长漂移低于0.06 nm,功率振荡低于0.35 dB,且单波长的频域信号中不存在高频分量。另一方面,通过将以上系统中的滤波器替换为二阶Lyot滤波器,还能对0.52 nm,0.78 nm和1.56 nm三种不同波长间隔进行切换,最终实现了波长间隔、波长数目、光谱范围的三种单独调谐功能。最后,本文对基于一阶Lyot双折射滤波器的激光系统进行进一步的性能优化研究。通过分别调节掺铒光纤、单模光纤及保偏光纤的长度,研究系统的调谐性能。当选择掺铒光纤长度为15 m,单模光纤长度为10 km,保偏光纤长度为8 m时,多波长激光器的输出特性较好。
[Abstract]:In recent years, tunable multi-wavelength erbium-doped fiber lasers have been widely used in the fields of high-capacity optical fiber communication, optical detection and optical fiber sensing.However, the existing tunable multi-wavelength erbium-doped fiber lasers usually use the tuning performance of comb filters to realize their tuning function. There are many problems such as single tuning function, multi-parameter control crosstalk and poor tuning controllability.In order to overcome the above problems, a novel tunable multi-wavelength laser is proposed, which has the function of single tuning of multiple parameters.In addition, the tuning performance of multi-wavelength erbium-doped fiber laser is studied theoretically and experimentally, and the optimized scheme of output characteristics of tunable erbium-doped fiber laser is proposed. The specific research contents are as follows: first,Based on the tunability of birefringence filter effect, a theoretical model of Lyot birefringent filter with loop structure is proposed. The output characteristics of first-order and second-order Lyot birefringence filters are studied by Jones matrix method.Numerical simulation is carried out.Secondly, a novel tunable multi-wavelength laser is proposed and proved.The tuning function is realized by combining the intensity coherent loss effect caused by the power symmetric nonlinear fiber loop mirror with the birefringence filter effect caused by the first-order Lyot birefringent fiber filter.Using the complementarity of nonlinear fiber loop mirror and Lyot birefringent filter in tuning function, single tuning of multiple output parameters is realized.By adjusting the first order Lyot filter, the peak position can be tuned continuously in a free spectral region.The coarse tuning function of the spectrum range can be realized by adjusting the NOLM, and the maximum shift of the spectrum is up to 8 nm.At the same time, we control the number of wavelengths by adjusting the polarization state of the NOLM input light and controlling the pump power respectively. The maximum number of wavelengths is as high as 18.The system has good stability, the wavelength drift is less than 0.06 nm, the power oscillation is less than 0.35 dB, and there is no high frequency component in the single wavelength frequency domain signal.On the other hand, by replacing the filter in the above system with the second-order Lyot filter, we can switch between 0.52 nm 0.78 nm and 1.56 nm, and finally realize the wavelength interval and the number of wavelengths.Three individual tuning functions in the spectral range.Finally, the performance optimization of laser system based on first order Lyot birefringence filter is studied.The tuning performance of the system is studied by adjusting the length of erbium-doped fiber, single-mode fiber and polarization-maintaining fiber respectively.When the length of erbium-doped fiber is 15m, the length of single-mode fiber is 10km and the length of polarization maintaining fiber is 8m, the output characteristic of multi-wavelength laser is better.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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