支持多轨道角动量模式的聚合物模斑转换器  

Polymer Spot Size Converter Supporting Multi-Orbital-Angular-Momentum-Modes

作　　者：雷思琛 闫扣儿 吴鹏飞[1,4] 王姣 谭振坤 杨霄鹏 Lei Sichen;Yan Kouer;Wu Pengfei;Wang Jiao;Tan Zhenkun;Yang Xiaopeng(School of Automation and Information Engineering,Xi'an University of Technology,Xi'an 710048,Shaanxi,China;School of Electronic Information and Artificial Intelligence,Shaanxi University of Science&Technology,Xi'an 710021,Shaanxi,China;School of Optoelectronic Engineering,Xi'an Technological University,Xi'an 710021,Shaanxi,China;Xi'an Key Laboratory of Wireless Optical Communication and Network Research,Xi'an 710048,Shaanxi,China)

机构地区：[1]西安理工大学自动化与信息工程学院,陕西西安710048 [2]陕西科技大学电子信息与人工智能学院,陕西西安710021 [3]西安工业大学光电工程学院,陕西西安710021 [4]西安市无线光通信与网络研究重点实验室,陕西西安710048

出　　处：《光学学报》2024年第13期88-94,共7页Acta Optica Sinica

基　　金：国家自然科学基金(62101313);陕西省自然科学基础研究计划面上项目(2024JC-YBMS-568);西安市高校院所科技人员服务企业项目(22GXFW0074);碑林区2023年应用技术研发储备工程项目(GX2342);陕西省重点研发计划工业领域(2024GX-YBXM-101)。

摘　　要：轨道角动量复用是一种复用技术,可有效提高通信系统的信道容量。将携带轨道角动量的光场耦合到光子集成电路中,对后续信号集成化处理具有重要意义。提出一种支持高阶轨道角动量(OAM_(±1)、OAM_(±2)、OAM_(±3))耦合的模斑转换器,将光纤中生成的轨道角动量模式经模斑转换器耦合到光子芯片,结果表明:模斑转换器可以对OAM_(±1)、OAM_(±2)、OAM_(±3) 6种模式实现光场稳定传输并压缩,耦合效率分别为90.7%、88.4%和86%,输出模式的纯度分别为95%、99%和97%。Objective Orbital angular momentum(OAM) is an intrinsic property of vortex beams characterized by helical wavefronts.Vortex beams can possess a topological charge of any integer value, with each charge being independent of the others. The superposition and multiplexing of an infinite number of topological charges can significantly enhance the channel capacity and spectral efficiency of communication systems. During the coupling process between optical fibers and waveguides, a technical challenge arises from low coupling efficiency due to mode field mismatch. This necessitates the introduction of a spot size converter(SSC) to improve coupling efficiency. Coupling OAM modes generated within optical fibers with photonic integrated circuits(PICs) holds great significance for providing high-purity mode light sources for on-chip integrated OAM communication. Furthermore, OAM facilitates subsequent signal integrated processing, thus achieving high-capacity system integration.Methods We propose a spot size converter that supports multiple OAM modes due to the characteristics of polymer optical waveguide materials, such as low loss, low power consumption, low refractive index, simple fabrication process,low cost, and support for large mode fields. The converter utilizes an SU-8 polymer for the core layer and SiO_2 material for the upper and lower cladding layers, featuring a regular polygonal cone structure. The spot size converter is simulated using the Finite Difference Time Domain(FDTD) method in Lumerical software.Results and Discussions We design a spot size converter featuring a regular polygonal cone structure. The optimized dimensional parameters are as follows: H_(1)=5 μm, H_(2)=15 μm, d_(1)=5 μm, d_(2)=2 μm, and L=350 μm, with the polygonal cone having 12 sides(Fig. 2). The mode field output from the optical fiber is coupled into the waveguide of the SU-8polygonal cone structure which is made of polymer material, along the input direction of the coupler. This process effectively transmits and compresses the

关 键 词：轨道角动量 光纤 光子集成电路 光纤-芯片耦合 模斑转换器 

分 类 号：TN256[电子电信—物理电子学]