聚合物脊形波导定向耦合电光开关的电极优化

Electrode Optimization of Polymer Directional Coupler Electro-optic Switch with Rib Waveguide Structure

给出了一种新型聚合物脊形波导定向耦合电光开关的结构模型和设计方法。应用保角变换法和镜像法分析了对称共面双电极的电场分布。为了获得最小的模式损耗和开关电压,优化了电极厚度、电极宽度和电极间距。为了使器件实现正常的开关功能,讨论了所能允许的开关电压的波动范围。模拟计算结果如下:脊形波导的芯宽度4.0μm,芯厚度1.5μm,脊高0.5μm,耦合间距3.0μm,优化后的电极厚度0.15μm,电极宽度3.0μm,电极间距3.5μm,耦合长度3082μm,开关电压5.43 V;当开关电压在5.28到5.59 V范围内波动时,器件的插入损耗小于0.60 dB,串扰小于-30 dB。与BPM仿真结果的对比表明,该优化方法具有较高的精度。

Novel structure and technique are proposed for a polymer directional coupler electro-optic switch with coplanar electrodes and rib waveguides. The electric field is analyzed using conformal transforming method and image method. To get the minimum loss and switching voltage, the electrode parameters are optimized. To realize normal switching function, the switching voltage shift is discussed. Optimization results show the core width, core thickness and rib height are 4.0 μm, 1.5μm and 0.5μm, respectively; the electrode thickness, width and gap are 0.15μm, 3.0μm and 3.5μm, respectively; the coupling length is 3 082μm, coupling gap is 3.0μm, and switching voltage is 5.43 V; the insertion loss and crosstalk are less than 0.60 dB and --30 dB, respectively, within the applied voltage range of 5.28～5.59 V. Compared with the simulation results of Beam Propagation Method, this optimized method possesses a high accuracy and presents meaningful instructions for the fabrication of such devices.