液晶平板光波导中耦合模式的研究  

Coupling Modes in Liquid Crystal Slab Optical Waveguide

作　　者：查正桃 张谦述 张耀进 周琪 ZHA Zheng-tao;ZHANG Qian-shu;ZHANG Yao-jin;ZHOU Qi(School of Physics and Astronomy,China West Normal University,Nanchong Sichuan 637009,China;School of Electronic Information Engineering,China West Normal University,Nanchong Sichuan 637009,China)

机构地区：[1]西华师范大学物理与天文学院,四川南充637009 [2]西华师范大学电子信息工程学院,四川南充637009

出　　处：《西华师范大学学报（自然科学版）》2022年第3期283-288,共6页Journal of China West Normal University(Natural Sciences)

基　　金：四川省科技厅应用基础研究计划项目(2014JY0024);南充市科技局科研基金项目(19YFZJ0090);西华师范大学英才科研基金项目(17YC056);西华师范大学大学生创新创业训练计划项目(cxcy2021318)。

摘　　要：光波导中耦合模式的研究是设计偏振模式控制器的重要环节。为了得到液晶倾斜角对液晶光波导中模式的调控规律,采用了以下步骤:首先,从向列相液晶耦合磁场方程得到了横向磁场分量的波动方程,并解析求解该波动方程得到模场场解的显式表达式;然后,根据边界条件得到了向列相液晶光波导中耦合模式的色散关系;最后,通过给出的数值案例分析得到了液晶分子倾斜角对模数曲线,模折射率以及模场分布的调控规律。结果表明,横向磁场分量之间的数量级关系易受液晶分子倾斜角的调控,而低阶模式的模折射率几乎不随液晶分子倾斜角变化。利用这一特性,有望实现基于液晶光波导的电控偏振旋转器和偏振模式转换器。The research of coupling modes in the optical waveguide is an important step in designing the polarization mode controller.The following steps are adopted to obtain the modulating law of liquid crystal tilt angle on the modes in liquid crystal optical waveguide(LCOW).Firstly,the wave equation of transverse magnetic field components is obtained from the coupled magnetic field equations of the nematic liquid crystal,which is analytically solved to obtain the explicit expression of the mode field solution.Then,the dispersion relation of the coupling mode in the nematic LCOW is obtained in accordance with the boundary conditions.Finally,the modulation law of liquid crystal molecular tilt angle on the mode number curve,mode refractive index and mode field distribution is obtained by numerical case analysis.The results show that the order of magnitude relationship between transverse magnetic field components is susceptible to the regulation of the tilt angle of liquid crystal molecule;however,the mode refractive index of the low order mode hardly changes with the increase of the tilt angle of liquid crystal molecule.It is expected that the electrically controlled polarization rotator and polarization mode converter based on LCOW will be realized by taking advantage of this characteristic.

关 键 词：向列相液晶 光波导 各向异性 耦合模式 色散关系 

分 类 号：TN252[电子电信—物理电子学]