利用数值模拟对扩散非线性机制下由光折变表面波诱导的薄层波导中导模的形成和特点进行了研究。采用分布傅里叶法对导模的传输特性进行了模拟。通过求解本征方程, 对光折变表面波诱导的薄层波导中存在的导波模式进行了数值求解。通过调节传播常数和波导参数的方法, 可以控制导模的阶数和传播波形。随着阶数的增加, 导模轮廓的对称性越来越差; 随着波导参数的增加, 导模的峰值振幅单调递增。导模的能量主要聚集在晶体薄层波导中靠近-c轴的一侧, 随着传播常数的增大, 导模能量先减小后增大, 且导模可以稳定传播。

Formation and property of guided modes were studied numerically in thin layer waveguide induced by photorefractive surface waves under diffusion nonlinearity. By employing the split-step Fourier method, the propagation of the guided modes were simulated. By solving the guided modes, the guiding properties of photorefractive surface wave-induced thin layer waveguide were analyzed. The orders and propagation waveform of guided modes can be controlled by adjusting the values of propagation constant and guiding parameter. With the increase of orders, the profile of the guided modes becomes more and more asymmetric. The peak amplitude of the guided modes increases monotonically with the guiding parameter. The energy of the guided modes is mainly concentrated in the thin waveguide near the -c axis of photorefractive crystal and becomes from small to large with an increase of the propagation constant. The stability properties of the guided modes are investigated numerically and it is shown that they can be stable.