Optimization of Manufacturing Process of Waveguides on Nonlinear Optical Polymer film

对光热极化法在非线性光学聚合物薄膜上制作光栅波导进行了数值模拟。建立了考虑聚焦激光加热和极化过程中分子偶极的时空变化的数学模型。操作因素的影响，即，研究了激光功率、光束直径、样品移动速度和电场强度对光栅结构的影响。结果，获得了用于生产具有高性能的波导的以下准则：应当选择激光束波长，以便在聚合物膜的整个厚度上均匀地加热，激光功率应当尽可能高而不会在膜中引起大的变形，激光束直径应当小于光栅的半个周期，工作台的移动速度应当慢，此外，还测量了带有分散红1（DR1）发色团侧基的聚甲基丙烯酸甲酯的旋转扩散系数和热扩散系数。

Numerical simulations of the manufacturing of waveguides with grating patterns on a nonlinear optical (NLO) polymer film using photothermal poling were carried out The mathematical model was constructed, in which spatial and temporal variations of molecular dipoles during heating with a focused laser beam and electrical poling were considered. The effects of operational factors, i.e., laser power, beam diameter, moving speed of a sample, and electric field strength, on the grating configuration were investigated. As a result, the following guidelines for producing a waveguide with high performance were obtained : the laser beam wavelength should be selected so as to heat uniformly throughout the thickness of the polymer film, the laser power should be as high as possible without causing large deformation in the film, the laser beam diameter should be smaller than half period of the grating, the moving speed of the stage should be slow, and the electric field strength should be as high as possible, if dielectric breakdown is to be avoided.In addition, measurements of the rotational diffusion coefficient and the thermal diffusivity of poly (methyl methacrylate) with Disperse Red 1 (DR1) chromophore side groups were carried out.