分布反馈光纤激光器传感阵列关键技术研究

发布时间：2018-05-08 02:36

  本文选题：光纤激光器 + 相干坍塌　； 参考：《国防科学技术大学》2016年博士论文

【摘要】：基于光纤光栅的分布反馈(Distributed Feedback,DFB)光纤激光器具备良好的激光输出特性和突出的本征波分复用性能,是构造多波长光纤激光传感阵列的良好载体,在光纤传感领域具有广泛的应用前景。目前已报道的DFB光纤激光器阵列最大规模仅为16基元,激光器阵列的相干坍塌效应是进一步扩大阵列规模的主要限制因素,腔外信号光及泵浦光注入是影响激光器基元噪声性能的重要因素。本文对DFB光纤激光器阵列中影响各激光器性能的关键物理问题进行研究,为扩展DFB光纤激光器阵列规模提供支撑。与独立工作的光纤激光器不同,DFB光纤激光器阵列中任一激光器都受到同频相干光反馈、非同频信号光注入以及泵浦光注入等因素影响,成为导致激光器基元性能恶化、阵列规模受限的主要原因。论文针对同频相干光反馈问题,研究相干坍塌对DFB光纤激光器阵列的影响及其抑制方法;针对非同频信号光注入问题,研究用于阵列功率整形的环境不敏感型长周期光纤光栅;针对泵浦光注入问题,研究泵浦致热引起的有源相移光栅非线性啁啾,以及DFB光纤激光器的热致失谐特性。此外,针对DFB光纤激光器阵列在高温极限条件的潜在应用需求,对掺杂光纤和长周期光纤光栅的高温特性进行系统测试。论文的主要研究成果和创新点如下:1、建立了基于双端耦合的二基元DFB光纤激光器阵列相干坍塌复合腔模型,提出基于相干坍塌特性的非对称DFB光纤激光器相移位置测量方法,通过优化阵列结构可使光纤激光器阵列长度增大近50m,为抑制相干坍塌效应、提高DFB光纤激光器阵列规模提供了一种可行途径。2、采用波导结构设计和低温退火技术在单模光纤上制作了同时对温度和应变不敏感的长周期光纤光栅,并观测到低温退火引起的波导结构纳米量级径向尺寸变化,为DFB光纤激光器阵列强度噪声优化设计提供支撑。3、实验测量了泵浦致热引起的有源相移光栅啁啾和DFB光纤激光器湮灭,得到了非线性热致失谐等效物理图像,提出基于泵浦调制的有源相移光栅相移补偿方法,为DFB光纤激光器阵列泵浦功率分配及各激光器性能优化提供指导。4、实验测量到掺杂光纤的高温增益恢复现象,实现长周期光纤光栅的高温再生,能够通过再生光栅分段线性温度响应确定光纤各波导层特征温度,为DFB光纤激光器阵列在高温极限条件的潜在应用提供实验基础。
[Abstract]:Distributed feedback distributed feedback DFB (DFB) fiber lasers based on fiber Bragg gratings have good laser output characteristics and outstanding intrinsic wavelength division multiplexing performance, so they are a good carrier for constructing multi-wavelength fiber laser sensor arrays. It has a wide application prospect in the field of optical fiber sensing. The largest scale of DFB fiber laser array reported at present is only 16 primitives, and the coherent collapse effect of the laser array is the main limiting factor for further expanding the array size. Extracavity signal light and pump beam injection are important factors that affect the noise performance of laser elements. In this paper, the key physical problems affecting the performance of DFB fiber laser arrays are studied, which provide support for expanding the scale of DFB fiber laser arrays. Different from the independent fiber laser, any laser in the DFB fiber laser array is affected by the coherent feedback of the same frequency, the optical injection of the nonidentical frequency signal and the injection of the pump light, which leads to the deterioration of the performance of the laser unit. The main reason for the limitation of array size. In this paper, the effect of coherent collapse on DFB fiber laser array and its suppression method are studied, and the environmentally insensitive long-period fiber grating for power shaping is studied. The nonlinear chirp caused by pump heat and the thermal detuning of DFB fiber laser are studied. In addition, the high temperature characteristics of doped fiber and long period fiber gratings are systematically tested for the potential applications of DFB fiber laser arrays in high temperature limit conditions. The main achievements and innovations of this paper are as follows: 1. A two-element DFB fiber array coherent collapse compound cavity model based on two-terminal coupling is established, and a phase shift measurement method for asymmetric DFB fiber laser based on coherent collapse characteristic is proposed. By optimizing the array structure, the length of the fiber laser array can be increased by nearly 50 ms. in order to suppress the coherent collapse effect, A feasible way to improve the scale of DFB fiber laser array is provided. Using waveguide structure design and low temperature annealing technique, long period fiber gratings are fabricated on a single mode fiber, which is not sensitive to temperature and strain at the same time. The nanoscale radial size change of waveguide structure caused by low temperature annealing is also observed. This paper provides support for the optimal design of intensity noise of DFB fiber laser array. The chirp of active phase shift grating caused by pump heat and the annihilation of DFB fiber laser are experimentally measured, and the equivalent physical image of nonlinear thermal detuning is obtained. An active phase-shifted grating phase shift compensation method based on pump modulation is proposed, which provides guidance for the pump power distribution of DFB fiber laser array and the performance optimization of each laser. The high temperature gain recovery phenomenon of doped fiber is measured experimentally. In order to realize the high temperature regeneration of long-period fiber grating, the characteristic temperature of each waveguide layer can be determined by the piecewise linear temperature response of the regenerated grating, which provides the experimental basis for the potential application of DFB fiber laser array in the high temperature limit condition.
【学位授予单位】：国防科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN248
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本文编号：1859601