有源光纤随机激光器调Q特性研究

发布时间：2018-04-21 04:18

本文选题：光纤激光器 + 随机激光　；参考：《电子科技大学》2017年硕士论文

【摘要】：调Q光纤激光器具有光束质量好、亮度高和波长可选择等诸多优点,其在精密加工、光纤通信和医疗应用等许多领域具有独特的应用价值。光纤随机激光器无纵模的特点,使得对于该种激光器输出特性的调控是当前研究的难点和热点。之前很多对基于受激布里渊散射的调Q型光纤随机激光器的研究中,时域输出调Q脉冲形状不规则,重复频率也不确定,在时域输出方面还不能做到有效的控制,因此,对于该种激光器时域输出脉冲的调节和规整十分重要。针对这些现状,本课题研究基于有源光纤的随机激光器时域调Q脉冲的产生和调控,首先实现了一种宽带反射型调Q光纤随机激光器,详细分析了时域调Q脉冲的输出特性,并通过对比实验验证了该激光器调Q脉冲的产生机制。然后,通过引入混合光纤谐振环结构,对宽带反射型调Q光纤随机激光器做了进一步的优化,提出并实现了一种谐振滤波型调Q光纤随机激光器,极大地优化了调Q脉冲的连续性和每一个调Q周期中子脉冲序列的形状及脉冲间隔。具体内容包括:搭建基于有源光纤的宽带反射型调Q光纤随机激光器系统,激光腔一端由环形器拉环构成反射镜,另一端由色散补偿光纤提供分布式反馈,在简单的光纤结构中结合了随机激光和调Q来产生随机的调Q脉冲输出,激光器阈值比较低,但每个调Q周期中子脉冲序列不规则;通过分别去掉激光腔一端的环形反射镜或色散补偿光纤来进行对比实验,然后分析和验证了随机调Q脉冲的产生机制。通过将宽带反射型调Q光纤随机激光器中的环形反射镜改为一个由两个10:90耦合器和一个环形器构成的混合型光纤谐振环结构,提出了一种谐振滤波型调Q光纤随机激光器,实现了对于随机脉冲从无序到有序的调控和规整:调Q脉冲序列基本是连续的,不再有较长时间范围的间断;调Q脉冲的幅度分布更集中一些,主要分布在0.3到0.5之间;单个调Q周期中包含多级具有相同脉冲形状、相同脉冲间隔、能量依次衰减的子脉冲序列,子脉冲序列变得更加规整。
[Abstract]:Q-switched fiber laser has many advantages, such as good beam quality, high brightness and choice of wavelength. It has unique application value in many fields such as precision machining, optical fiber communication and medical treatment. The characteristic of fiber random laser without longitudinal mode makes it difficult and hot to control the output characteristics of this kind of laser. In previous studies of Q-switched fiber random lasers based on stimulated Brillouin scattering, the output Q-switched pulses in time domain are irregular in shape and uncertain in repetition frequency, so they can not be effectively controlled in time domain output. It is very important for this kind of laser to adjust and adjust the output pulse in time domain. In order to solve these problems, the generation and control of time-domain Q-switched pulses of random lasers based on active fiber are studied in this paper. Firstly, a kind of wide-band reflected Q-switched fiber random lasers is realized, and the output characteristics of time-domain Q-switched pulses are analyzed in detail. The generation mechanism of Q-switched pulse is verified by contrast experiment. Then, by introducing the hybrid fiber resonant ring structure, the broad-band Q-switched fiber random laser is further optimized, and a resonant filter Q-switched fiber random laser is proposed and realized. The continuity of Q-switched pulses and the shape and interval of each Q-switched periodic neutron pulse sequence are greatly optimized. The main contents are as follows: a wide-band Q-switched fiber random laser system based on active fiber is built. One end of the laser cavity is composed of ring loop, the other end is distributed feedback provided by dispersion compensation fiber. In the simple fiber structure, random laser and Q-switched are combined to produce random Q-switched pulse output. The threshold of the laser is relatively low, but each Q-switched periodic neutron pulse sequence is irregular. By removing the ring mirror at one end of the laser cavity or the dispersion compensation fiber, the mechanism of random Q-switched pulse generation is analyzed and verified. By changing the ring mirror of broad-band Q-switched fiber random laser into a hybrid fiber resonant ring structure composed of two 10:90 couplers and a ring device, a resonant filter Q-switched fiber random laser is proposed. The modulation and regularity of random pulses from disorder to order are realized: the sequence of Q-switched pulses is basically continuous, and the amplitude distribution of Q-switched pulses is more concentrated, mainly ranging from 0.3 to 0.5; A single Q-switched cycle consists of sub-pulse sequences with the same pulse shape, the same pulse interval, and the energy decay in turn, and the sub-pulse sequence becomes more regular.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248

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