A strategy for preparing broadband polymer based optical waveguide amplifiers:doping low crystal field symmetric nanocrystals in polymer matrix as gain media  

宽带聚合物光波导放大器的制备策略:在聚合物基质中掺杂低晶场对称纳米晶体作为增益介质

作　　者：Hao Cui Zixuan Jiang Yu Yang Siliang Tao Shuang Wu Jing Yin Fei Wang Guanshi Qin Fanchao Meng Dan Zhao Weiping Qin 崔皓;姜子炫;杨育;陶思亮;吴双;尹晶;王菲;秦冠仕;孟凡超;赵丹;秦伟平

机构地区：[1]State Key Laboratory on Integrated Optoelectronics,College of Electronic Science&Engineering,Jilin University,Changchun 130012,China

出　　处：《Science China Materials》2024年第12期3908-3916,共9页中国科学（材料科学）（英文版）

基　　金：supported by the National Key Research and Development Program of China(2021YFB2800502);the National Natural Science Foundation of China(U22A2085 and 12174150)。

摘　　要：Optical waveguide amplifiers are essential devices in integrated optical systems,with their gain bandwidths directly influencing the operating wavelengths of optical circuits.Previous Er^(3+)-doped polymer optical waveguide amplifiers have been limited to amplifying signals within the C-band.To achieve broadband polymer optical waveguide amplification,we propose the use of nanocrystals with low crystal field symmetry to extend the working bandwidth.Our approach utilizes LiYF_(4):Yb,Er nanoparticles embedded in poly(methyl methacrylate)as the gain medium,enabling signal amplification from most of the S-band to the whole(C+L)band.The low crystal field symmetry of the LiYF_(4)host significantly splits the^(4)I_(13/2)and^(4)I_(15/2)levels of Er^(3+)ions owing to the crystal field effect,facilitating broadband down-conversion luminescence under 980-nm excitation.Furthermore,a fluorescence kinetic analysis confirms that the broadband luminescence of Er^(3+)arises from significant energy-level splitting caused by the crystal field effect.Under 980-nm excitation,the amplifiers exhibited relative gains of approximately 12.6 dB at 1535 nm,7.4 dB at 1480 nm,and 3.7 dB at 1610 nm.The Er^(3+)-doped broadband polymer optical waveguide amplifier was successfully prepared.光波导放大器是集成光学系统中必不可少的器件.它们的增益带宽直接决定了集成光路的工作波长.以往掺杂Er^(3+)的聚合物光波导放大器只能放大C波段的光信号.为了获得宽带聚合物光波导放大器,我们提出了一种策略:使用具有低晶体场对称性的纳米晶体来实现光波导放大器工作带宽的宽.采用LiYF_(4):Yb,Er-PMMA复合聚合物作为增益介质的聚合物波导放大器可以实现整个(C+L)波段和大部分S波段的信号放大.由于LiYF_(4)基质的晶体场对称性较低,Er^(3+)离子的^(4)I_(13/2)和^(4)I_(15/2)能级在晶体场效应作用下发生了强烈的J劈裂,从而实现了Er^(3+)离子的宽带发光.此外,荧光动力学分析证实了Er^(3+)的宽带发光是由于晶体场效应导致的显著能级劈裂、子能级之间的跃迁而引起的.在980 nm激发下,放大器在1535 nm处的相对增益约为12.6 dB,在1480 nm处为7.4 dB,在1610 nm处为3.7 dB.本文成功实现了掺铒的聚合物光波导放大器工作带宽展宽.

关 键 词：polymer optical waveguide amplifiers crystal field effect crystal field symmetry energy level splitting 

分 类 号：TN722[电子电信—电路与系统] TB383.1[一般工业技术—材料科学与工程] TQ317[化学工程—高聚物工业]