级联反谐振微环波束成形网络芯片的自动标定研究  

Automatic Calibration of Optical Beamforming Network Chip Based on Cascaded Anti-Resonant Microring

作　　者：孙寒玮 陆梁军 金敏慧 刘娇 周林杰[1,2] 陈建平 Sun Hanwei;Lu Liangjun;Jin Minhui;Liu Jiao;Zhou Linjie;Chen Jianping(State Key Laboratory of Advanced Optical Communication Systems and Networks,Shanghai Jiao Tong University,Shanghai 200240,China;SJTU-Pinghu Institute of Intelligent Optoelectronics,Pinghu 314200,Zhejiang,China)

机构地区：[1]上海交通大学区域光纤通信网与新型光通信系统国家重点实验室,上海200240 [2]上海交大-平湖智能光电研究院,浙江平湖314200

出　　处：《中国激光》2022年第11期205-215,共11页Chinese Journal of Lasers

基　　金：国家重点研发计划(2018YFB2201702,2019YFB2203200,2019YFB1802903);国家自然科学基金(62075128,62090052,62135010)。

摘　　要：本文对基于级联反谐振微环的1×N树状波束成形网络芯片进行了理论分析。该结构采用反谐振微环实现低延迟抖动、大带宽的光学真延迟,并利用树状结构来减少延迟单元的数量,可用于宽带大规模微波光子相控阵天线系统中。针对微环单元初始状态随机的问题,本团队构建了一套自动化标定系统,利用光谱与微波延迟谱联合迭代优化来精准控制微环延迟量和谐振波长。测试了基于氮化硅的1×8低损耗波束成形网络芯片中的最长路径,实现了路径中所有21个级联微环的延迟离散调节,测得最大延迟量为560 ps,延迟抖动小于11.2 ps;同时验证了3个微环的延迟连续调节,3个微环在0~8 GHz带宽内的延迟抖动小于7.5 ps。本系统可以消除微环间热串扰对微环状态标定的影响,同时降低了芯片与硬件系统的复杂度。Objective Microwave phased array antennas(PAAs)have attracted considerable interest owing to their advantages of rapid and accurate beam steering.Traditional PAAs based on electronic phase shifters suffer from the disadvantages of steering angle and instantaneous bandwidth of the radio-frequency(RF)signal due to the beam squinting problem.Integrated optical beamforming networks(OBFNs)use optical true time delay lines(OTTDLs)to broaden the instantaneous bandwidth.The processing RF signal in the optical domain also brings the advantages of low loss,compact size,light weight,and zero electromagnetic interference.Therefore,they can play an important role in broadband large-scale PAA systems.Moreover,the OBFNs can be integrated with other microwave photonic systems,such as optoelectronic oscillators,photonic analog-to-digital converters,and optical channelizing filters to realize fully integrated microwave photonic radars.The most important components in the integrated OBFNs are the OTTDLs.Integrated OTTDLs with a broad bandwidth and large delay tuning range are in high demand.Among the various integrated OTTDL structures,cascaded tunable microring resonators(MRRs)are promising owing to their continuous and broadband delay tuning.Previously,we demonstrated a cascaded-MRRs-based OTTDL chip working at the anti-resonant wavelength.It exhibited the advantages of broadband response with low delay fluctuation,high scalability,and simple control schemes.In this work,we proposed a 1×N binary tree OBFN chip based on cascaded MRRs(Fig.1).The binary tree topology interlaces the power splitters with the OTTDLs,which effectively reduces the number of delay elements.Due to the random phase errors of MRRs and the thermal crosstalk upon tuning,we proposed and demonstrated an automatic calibration method to facilitate the state calibration of OTTDLs.Methods First,we theoretically investigated the working principle of the OBFN using the transfer matrix method.From the simulated delay spectra,we determined that the anti-resonant MRRs h

关 键 词：光学器件 集成光器件 微环谐振器 光延迟线 反馈控制算法 

分 类 号：TN256[电子电信—物理电子学]