间隔轨道角动量的复合涡旋光束编/解码  

Encoding/Decoding of Composite Vortex Beams with Spaced Orbital Angular Momentums

作　　者：吴鹏飞[1] 王小蝶 王姣 谭振坤 贾致远 Wu Pengfei;Wang Xiaodie;Wang Jiao;Tan Zhenkun;Jia Zhiyuan(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 Optoelectronical Engineering,Xi'an Technological University,Xi'an 710021,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

出　　处：《光学学报》2023年第11期249-256,共8页Acta Optica Sinica

基　　金：陕西省教育厅服务地方专项计划项目(20JC027);西安市高校院所科技人员服务企业项目(22GXFW0074);国家自然科学基金(62001363,62101313);陕西省科技厅重点研发计划-工业领域一般项目(2022GY-100)。

摘　　要：为提高传输系统的信道容量、编码效率以及解码的可靠性,本文提出了一种基于轨道角动量(OAM)模态和径向模态的复合涡旋光束编码方法。使用5位二进制序列对两束光[一束是具有固定径向模态和OAM模态的拉盖尔-高斯(LG)涡旋光束,另一束是具有4种径向模态(p=0,1,2,3)和8种相同间隔OAM模态(l=±3,±5,±7,±9)的LG涡旋光束]叠加产生的32组不同类型的复合涡旋光束光强分布图进行编码。将32组复合涡旋光束依据本文提出的映射关系转换成32组单束LG涡旋光束,依次照射在提出的x、y轴方向周期渐变光栅上,通过光栅的远场衍射光斑可成功检测出发射单束LG涡旋光束的参数p和l,且不受OAM模态和径向模态增加的影响,最终可实现正确解码。Objective With the advantages of high flexibility,high security,and large communication bandwidths,vortex beams play an important role in many fields,such as quantum entanglement,spatial optical communications,particle manipulation,and optical microscopy.In optical communication applications,the orbital angular momentums(OAMs)of vortex beams can be used as a new encoding method for highdimensional information encoding.This method can not only achieve modedivision multiplexing and scale the capacity of optical communications but also improve the channel capacity and spectral efficiency of optical communications.It thus provides a potential solution for future highspeed,high-capacity,and highspectralefficiency optical communication technologies.This study proposes an encoding method based on OAM and radial modes for composite vortex beams.It uses a 5-bit binary sequence to encode the light intensity distributions of 32 different composite vortex beams generated by the coaxial superposition of two vortex beams.The topological charge and radial index of the incident vortex beam are detected by the proposed graduallychangingperiod gratings for decoding purposes.The research results of this study provide a theoretical basis for extending the applications of the OAM modes of vortex beams in the encoding and decoding field.Methods To generate large topological charges and make demodulation easier,this study proposes an optical communication method and system featuring the encoding of composite vortex beams with spaced OAM modes.Specifically,a LaguerreGaussian(LG)vortex beam with fixed OAM and radial modes is coaxially superposed with an LG vortex beam with four radial modes(p=0,1,2,3)and eight equally spaced OAM modes(l=±3,±5,±7,±9)to generate and further encode the light intensity distributions of 32 different composite vortex beams with a 5-bit binary sequence.Then,Eq.(3)is used to convert the 32 composite vortex beams into 32 single LG vortex beams,which will irradiate the proposed graduallychangingperiod gratings

关 键 词：物理光学 复合涡旋光束 轨道角动量 径向模态 周期渐变光栅 远场衍射光斑 

分 类 号：P427.1[天文地球—大气科学及气象学]