空间四波导的传输特性分析与应用

Propagation Characteristic Analysis and Applications of Spatial Four-Waveguide System

借助于Marcatili原理,将二维分布的空间四波导分解为波导横截面上两个垂直的五层平板波导的组合,提出适于用分离变量处理的解析模型。利用微扰方法对模型与实际结构的偏差进行了一级修正,给出了传播常量的一级和二级近似表达式、静态模场分布、耦合系数以及传输特性公式,并比较了此方法与有限差分直解波动方程和光束传输两种数值方法的计算结果,探讨了该模型的适用性和优点,并检验了其精确性。应用该理论设计了包含光纤到户交换机常用的1.31μm,1.49μm,1.55μm波长的四波长粗波分复用器件,其插入损耗为0.68 dB,通过进一步优化分离的输出端口和波导结构可以获得更好的性能。

By employing Marcatili＇s principle, the two-dimensional spatial four-waveguide system is decomposed as two perpendicular five-layer slab waveguides independently in the cross-section of the waveguides. The analytical model that can be interpreted appropriately by variable seperation method is proposed. The first order correction for deviations of the model and practical structure is done by perturbation theory. The expressions of the first and second order propagation constants, static field distributions, coupling coefficient and propagation characteristic are presented. The feasibility and accuracy of the model are demonstrated by comparing the calculation results with finite difference solving semi-vector wave equation and beam propagation method. A coarse wavelength demultiplexer based on spatial four-waveguide system, including three common wavelengths 1.31 μm, 1.49 μm, and 1.55 μm of the triplex transistor in today＇s fiber-to-home, is designed with the insertion loss 0.68 dB. Further optimization of the separate outputs and waveguide structure can obtain higher qualities.