基于级联非对称Y分支的紧凑宽带高效的LP01-LP11a模式转换器  

Compact,Broadband,and Efficient LP_(01)-LP_(11a)Mode Converter Based on Cascaded Asymmetric Y-Junction

作　　者：张豪 邓佳瑶 王梦柯 马小霞 陈开鑫 Zhang Hao;Deng Jiayao;Wang Mengke;Ma Xiaoxia;Chen Kaixin(School of Optoelectronic Science and Engineering,University of Electronic Science and Technology of China,Chengdu 611731,Sichuan,China)

机构地区：[1]电子科技大学光电科学与工程学院,四川成都611731

出　　处：《中国激光》2024年第6期171-178,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(62075027);四川省重点研发计划(2020YFSY0003);深圳市关键技术研发计划(JSGG20210802154413040)。

摘　　要：提出了一种基于级联非对称Y分支的紧凑、宽带、高效的LP_(01)-LP_(11a)模式转换器。制作的聚合物波导模式转换器具有1.5 mm×14.0μm的紧凑尺寸,对于C+L波段的x偏振和y偏振光,其模式转换效率大于98%,串扰小于-17.5 dB,插入损耗低于5.8 dB。所提出的模式转换器可以应用在宽带模分复用传输系统中。Objective The current information capacity of communication systems based on single-mode fibers(SMFs)is approaching its physical limits.To solve this problem,spatial-division multiplexing based on mode-division multiplexing(MDM)has been intensively investigated.Due to its orthogonal characteristics,MDM can help realize more multiplexed channels,and thus the capacity of existing optical fiber communications can be enhanced.Mode converters are critical devices in optical-fiber communication systems and are essential for improving the performance of future MDM systems applicable in long-distance and high-capacity optical-fiber communication.Mode-conversion efficiency is a major index of mode converters.Mode converters based on asymmetric Y junctions on polymer platforms offer the advantages of low cost,high fabrication tolerance,and wide bandwidth.Thus,the design and fabrication of mode converters with compact structures and high mode-conversion efficiencies based on asymmetric Y junctions on polymer platforms are essential to meet the increasing demands in data traffic.Methods The proposed mode converter consists of two identical inversely connected asymmetric Y junctions.The stem of the Y junction is a straight two-mode waveguide designed to support only the Ei11 and Ei21 modes(i=x or y,indicating the polarization direction),which correspond to the LP01 and LP11a modes(polarized in the i direction)of the optical fiber,respectively.This two-mode core gradually branches into two single-mode cosine S bends with different widths,forming an asymmetric Y junction.Based on the mode evolution principle of the asymmetric Y junction,the parameters of the proposed mode converter based on a cascaded asymmetric Y junction(Fig.1)are optimized in this study.These parameters include the widths of the core(w1),arms A and D(w2),and arms B and C(w3),as well as the length of the arm(L),width of the Y-junction end(w4),and distance between the two Yjunction ends(w5).A three-dimensional finite-difference beam-propagation method(3DFD-BPM

关 键 词：光纤光学 光学器件 模式转换器 模分复用 聚合物波导 集成光学 非对称Y分支 

分 类 号：TN256[电子电信—物理电子学]