High channel-count comb filter based on multi-concatenated sampled chirped fiber Bragg gratings

A high channel-count comb filter based on multi-concatenated sampled chirped fiber Bragg gratings(MC-SCFBGs) is proposed and optimally designed by using several chirped gratings with different fundamental grating periods,instead of non-grating sections of SCFBGs.The numerical simulations of the reflection spectra show that the channel spacing and the channel bandwidth in MC-SCFBGs are smaller than those in multi-concatenated chirped fiber Bragg gratings(MC-CFBGs) and that the spectral bandwidth of MC-SCFBGs can be greatly broadened by increasing the cascade number of the grating sections in each sampling period.     

基于级联相移线性啁啾光纤光栅的梳状滤波器设计

为了获得反射带宽大、信道间隔均匀的高性能梳状滤波器,提出一种基于级联相移线性啁啾光纤光栅的新型梳状滤波器的结构设计.利用传输矩阵法和法布里-珀罗谐振腔理论,数值分析了该梳状滤波器中啁啾光栅的级联方式、啁啾量、折射率调制量和级联处的相移量对光栅反射谱特性的影响.结果表明:对应不同的级联方式,反射峰存在疏密变化,即两个级联光栅的啁啾量同号时,反射峰分布均匀对称,可设计均匀滤波器;而两个啁啾量异号时,反射峰呈现出疏密渐变的特性,可设计非均匀滤波器.此外,光栅啁啾量增加,反射谱带宽增大,但是反射率降低,而增大折射率调制量,可以提高反射率;级联处的相移量改变时,每个反射峰位置发生移动,从而可以通过改变相移量选择滤波窗口.     

钙钛矿材料在环境催化领域的应用现状及进展

日益严重的环境问题和有限的资源促使人们积极探索提高污染物处理效率,多相催化剂在环境污染高效治理中扮演着重要的角色,因此,高活性和高稳定性新型多相催化剂的开发成为一项非常有吸引力和具有挑战性的任务。钙钛矿材料因其高催化活性和稳定的晶体结构成为环境催化领域的研究热点。本文综述了钙钛矿材料特性、制备方法、新型钙钛矿材料发展现状和在环境催化领域的应用现状,并对其面临的挑战及未来发展方向进行了讨论。