高速光学模数转换器的分析

Analysis of High-Speed Optical Waveguide Analog-to-Digital Converter

详细分析了由x切LiNbO3干涉式共面波导行波调制器阵列构成的模数(A/D)转换器,包括其研究进展。采用保角变换方法分析了梯形共面波导电极参数(包括电极厚度、缓冲层厚度与中心电极和接地电极的边沿倾角β1,βg)与转换器的带宽、损耗、特征阻抗和驱动功率的关系。β1=βg=10°,电极厚度为3μm时,4位A/D转换器的工作带宽为7.3GHz,所需驱动功率为6.7W。数值仿真结果表明,采用梯形共面波导调制器阵列设计分辨率适中的高速A/D转换器是可行的。

The detailed analysis of a high-speed optical analog-to-digital (A/D) converter consisting of an array of coplanar waveguide (CPW) traveling-wave interferometric modulators on x-cut LiNbO3 substrate has been performed. The development of this kind of optical A/D converters is described. The relation of small-signal bandwidth, impedance, microwave attenuation parameters and drive power to the trapezoidal CPW electrode parameters including the electrode thickness, the buffer layer thickness to the edge inclination of the central electrode and ground planes β1,βg by coformal mapping are analyzed. When the electrode thickness is 3μm and β1=βg=10°,the bandwidth of 4-bit A/D converter is 7.3GHz and the requirement of drive power is 6.7W. The numerical results show that it is feasible to design a high-speed A/D converter using traveling-wave interferometric modulator with moderate resolution.