基于双发色团非线性分子的掩埋型共面波导电极聚合物电光调制器研究

Poled polymers have merits of low dielectric constant and high electro-optic (EO) coefficient contrasted with inorganic materials, such as LiNbO3. The half-wave voltage of poled polymer EO modulator can be reduced to 0.65V, while the 3dB bandwidth is improved to 100GHz. Thus, poled polymer modulator is a competitive device in the application of broadband optical fiber communication systems. The nonlinear relaxation in optical waveguide of high polarization chromophore must be resolved before the practical application. This project adopts the method based on the electrical and chemical compatibility to optimize performances of polymer EO modulators. The effect of improving dielectric surroundings and poling process on the basis of interface morphologies between layers and poled electric charges is revealed to enhance the EO stability and reduce optical losses. The interaction mechanism of binary chromophoreS, which is in favor of enhancing nonlinear optical performance, alleviating EO relaxation and optical losses, is studied. The DC drift induced by the electric relaxation of claddings is suppressed and the electro-optic overlap factor is enhanced through the application of buried coplanar waveguide (CPW) electrode and laser assistant poling. Device characteristics of optical insertion loss lower than 8dB, effective EO coefficient larger than 25pm/V with time relaxation within 5% in 2000h, 3dB bandwidth larger than 20GHz, are expected to be realized. This project provides important theoretical guide and experimental data for promoting the practical application of polymer modulators.

极化聚合物相比于铌酸锂等无机材料，具有介电常数低、电光系数高的优点。聚合物电光调制器半波电压可降至0.65V，3dB带宽可达100GHz以上，是未来宽带光纤通信系统中极具竞争力的核心器件。高极化率发色团应用于波导结构中，存在极化效率降低和非线性弛豫问题，是聚合物调制器实用化面临的主要挑战。本项目从提高波导材料介电兼容性、优化层间界面形态和极化电荷的角度，揭示改善发色团介质氛围对增强波导电光稳定性和降低光损耗的作用，阐明分子极性对发色团溶解度和双发色团分子电光活性的影响，通过掩埋型共面波导电极提高电光重叠积分因子Γ和极化效率，抑制包层电弛豫导致的线性工作点漂移，采用光辅助极化方法制备基于SH1/DR1-PMMA的电光调制器，实现Γ×γ33＞25pm/V且2000h内衰减＜5%，光插入损耗＜8dB，3dB带宽＞20GHz。该项目为推动聚合物电光调制器实用化提供了重要的理论指导和实验依据。

DWDM系统的核心部件发射模块中的高速外调制器性能对系统的传输距离和传输容量起着重要作用。极化聚合物相比于铌酸锂等无机材料，具有介电常数低、电光系数高的优点。聚合物电光调制器的半波电压可降至0.65V，3dB带宽可达100GHz以上，是未来宽带光纤通信系统中极具竞争力的核心器件。高极化率发色团应用于波导结构中，会出现极化效率降低和非线性弛豫现象，是聚合物调制器实用化面临的主要挑战。. 本研究利用UV-Vis吸收谱表征了光辅助极化时客体分子在BCOG中的溶致色散和谱线展宽，根据介电常数和序参数的变化，证实了客体发色团掺杂比例与电光活性的关系，揭示了LAP极化中光功率、极化温度和电压对BCOG电光活性的影响；通过研究包层材料对芯层中BCOG发色团形态的影响，从化学和电学兼容性的角度揭示了波导介质结构与电光弛豫和光损耗的关系，通过优化波导材料的兼容性，实验证明了改善发色团介质氛围和极化工艺可以提高波导电光稳定性，降低光损耗；以波导介质结构为研究对象，在充分考察波导材料电学及化学兼容性的基础上，从极化电场结构、极化效率、光损耗等角度揭示了优化波导材料性能匹配对提高BCOG电光波导非线性稳定性的关键作用；从主客体分子极性差异的角度，揭示了发色团分子比例对BCOG电光活性的作用，并将BCOG应用于掩埋型CPW电极调制器，通过电极与波导的共面结构减小包层分压导致的极化效率降低，增强了电光重叠积分因子，抑制了由于芯层-包层电导率差异导致的直流漂移。. 实验中，实现了SH1/DR1-PMMA非线性材料的有效极化，γ33＞40pm/V且2000h内衰减＜5%；采用掩埋型CPW电极，制备了M-Z型电光调制器，在工作波长1550nm下，光插入损耗＜8dB，3dB带宽＞20GHz，Γ×γ33＞25pm/V且2000h内衰减＜5%；发表SCI检索学术论文20篇，申请发明专利3项，授权1项；协助培养博士研究生3人，硕士研究生8人，毕业5人。 . 本项目研究中，从有源材料和无源材料兼容性出发增强波导稳定性的方法，对于聚合物电光调制器的实用化，具有一定的理论意义和实验指导价值，其研究成果为非线性材料应用于聚合物电光调制器，提供可靠的实验依据和理论指导。

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