Parfenov Mikhail, Agruzov Petr, Tronev Aleksandr, Ilichev Igor, Usikova Anna, Zadiranov Yurii, Shamrai Aleksandr
Ioffe Institute, Politekhnicheskaya 26, 194021 St. Petersburg, Russia.
Nanomaterials (Basel). 2023 Oct 13;13(20):2755. doi: 10.3390/nano13202755.
An approach for filtering the fundamental mode in an integrated optical modulator with multimode waveguides based on etched thin lithium niobate nanofilms is presented. It is shown that metal electrodes can be used as a modal filter to suppress high-order modes in wide multimode ridge waveguides and, consequently, to provide their quasi-single-mode regime of operation. The influence of the gap between the electrodes and its displacement relative to the waveguide symmetry axis is analyzed for various configurations of waveguides. The conditions for quasi-single-mode light propagation with suppression of high-order modes of more than 90 dB/cm are found. The influence of fabrication errors on the efficiency of modal filtering is discussed. Efficient electro-optical modulation with an equivalent voltage-length product of 4 V∙cm has been experimentally demonstrated on integrated optical phase modulator samples fabricated using conventional contact photolithography. The proposed topological solution can be further used for the fast and cheap fabrication of TFLN modulators by conventional contact photolithography. The proposed modal filtering can also be used in other waveguide topologies and in more complex waveguide devices.
提出了一种基于蚀刻薄铌酸锂纳米薄膜的多模波导集成光调制器中基模滤波方法。结果表明，金属电极可作为模式滤波器，抑制宽多模脊形波导中的高阶模式，从而实现其准单模工作状态。针对各种波导配置，分析了电极之间的间隙及其相对于波导对称轴的位移的影响。找到了抑制高于90 dB/cm的高阶模式的准单模光传播条件。讨论了制造误差对模式滤波效率的影响。在使用传统接触光刻制造的集成光相位调制器样品上，通过实验证明了等效电压-长度积为4 V∙cm的高效电光调制。所提出的拓扑解决方案可进一步用于通过传统接触光刻快速廉价地制造TFLN调制器。所提出的模式滤波也可用于其他波导拓扑结构和更复杂的波导器件中。
