线性啁啾光栅的分段变迹优化和基于自适应遗传算法的光栅重构  

Piecewise apodized optimization and parameter reconstruction based on self-adaptive genetic algorithm for linear chirped fiber grating

作　　者：孙瑞霞[1] 赵发[1] 李炜[1] 

机构地区：[1]安徽工程大学电气传动与控制安徽省重点实验室,安徽芜湖241000

出　　处：《光电子．激光》2018年第1期28-33,共6页Journal of Optoelectronics·Laser

基　　金：安徽省高等学校自然科学研究(KZ00216024);安徽省高等学校优秀青年人才基金(2012SQRL219)资助项目

摘　　要：针对线性啁啾光栅存在的反射谱顶部有震荡、中心谱两侧出现旁瓣、群时延线性度差和色散曲线不够平稳等问题,在特性分析的基础上,提出分段变迹优化方法,探寻了有效的变迹函数和最佳分段比例。对光栅的时延和反射谱特性进行综合表征,从综合指标出发进行光栅重构,提出一种基于自适应遗传算法(IGA)的重构方法,并在算子和算法方面进行深入探索。结果表明,分段变迹后群时延线性区域增大,色散曲线更平稳,同时有效降低了变迹造成的带宽压缩程度。此重构方法十分有效,重构后的光栅长度、调制深度和啁啾系数误差分别为0.04%、0.532%和0.31%。重构的反射谱、时延曲线均与实际结果基本吻合。还可以根据不同实际应用的要求进行重构,因此实用性更好。The top of reflection spectrum is oscillatory,side lobes appear on both sides of reflection spectrum, linearity of delay curve is not good, and dispersion curve is not smooth for linear chirped fiber grating. In order to solve the above problems, piecewise apodized optimization was adopted, and effective apo- dization functions and optimal piecewise apodization ratio are explored on the basis of characteristic anal- ysis of linear chirped fiber grating. The characterization and evaluation of delay and reflection spectrum are presented. From the comprehensive index,an adaptive genetic algorithm （IGA） is explored from the aspects of genetic operator and algorithm used for the reconstruction of fiber grating parameters. Experi- mental results show that the linear region of delay curve increases, the dispersion curve has been more stable,and compression level of bandwidth effectively reduces after piecewise optimization. The IGA reconstruction method is very effective, and has higher precision. Errors of the length, the modulation depth and the chirp coefficient of fiber grating respectively are 0.04% ,0. 532% and 0.31% after IGA reconstruction. Delay and reflection spectrum are all both consistent with the actual results. In addition, this IGA reconstruction method can also meet the requirements of many other practical applications.

关 键 词：啁啾光栅 优化 分段变迹 参数重构 综合指标 自适应 

分 类 号：TN25[电子电信—物理电子学]