LiNbO3电光调制器行波电极优化设计

分析了厚电极厚缓冲层的共面波导Mach-Zehnder行波电极LiNbO3光调制器，讨论了电极厚度和缓冲层厚度对调制器特性参数的影响，得到了调制器的有效折射率、特征阻抗、半波电压及损耗系数等参数。通过对比分析，选择合适的电极厚度和缓冲层厚度，优化调制器性能，近似满足速度和阻抗匹配，实现了图宽带调制。
关 键 词 共面波导; 保角变换; 速度匹配; 阻抗匹配; 宽带光调制

Abstract The Mach-Zehnder traveling wave LiNbO3 optical modulator with thicker electrodes and relatively thicker SiO2 buffer layer have been analysed using conformal mapping, taking into account the dependence of the modulation characteristics on the thickness of electrodes and buffer layer at the same device. The relation between the parameters and the modulation characteristics, such as effective index, characteristic impedance, half-wavelength voltage and conductor loss, have been obtained to select the proper thickness of the electrodes and buffer layer to optimize the performance of the modulator. By using the calculation results, the velocity matching and impedance matching are achieved approximately to realize the broadband modulation.
Key words coplanar waveguide; conformal mapping; velocity-matching; impedance-matching; broadband optical modulation