利用交替追赶有限差分技术处理近轴标量波方程，建立了一种三维有限差分光束传播法。此方法收敛性好，可处理具有较复杂折射率分布的波导结构，并且在计算规则波导时传播方向的计算步长可取得较大。利用这种方法对电光诱导光波导器件和单模光纤的传输特性进行了分析。

A new three-dimensional finite difference beam propagstion method (3D-FDBPM) is proposed.We use the finite difference technique and the Alternating Direction Implicit Method(ADI)to deal with the scalar paraxisl wave equation and establish the 3D-FDBPM. This method is very robust and can be used for various Photonic devices with complex index profile and allows large propagation steps along the propagation direction of the waveguide structure with uniform waveguides. This method is used to analyze the electrooptically induced waveguide configuration and single-mode fiber.