Efficient and wideband acousto-optic modulation on thin-film lithium niobate for microwave-to-photonic conversion

作     者：AHMED E.HASSANIEN STEFFEN LINK YANSONG YANG EDMOND CHOW LYNFORD L.GODDARD SONGBIN GONG 

作者机构：Holonyak Micro and Nanotechnology LaboratoryDepartment of Electrical and Computer EngineeringUniversity of Illinois at Urbana-ChampaignUrbanaIllinois 61801USA 

出 版 物：《Photonics Research》 (光子学研究（英文版）)

年 卷 期：2021年第9卷第7期

页      面：1182-1190页

核心收录：

学科分类：080901[工学-物理电子学] 080902[工学-电路与系统] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0803[工学-光学工程] 

基　　金：NASA (80NSSC17K052) 

主　　题：wideband millimeter waveguide 

摘      要：Microwave photonics,a field that crosscuts microwave/millimeter-wave engineering with optoelectronics,has sparked great interest from research and commercial sectors. This multidisciplinary fusion can achieve ultrawide bandwidth and ultrafast speed that were considered impossible in conventional chip-scale microwave/millimeterwave systems. Conventional microwave-to-photonic converters,based on resonant acousto-optic modulation,produce highly efficient modulation but sacrifice bandwidth and limit their applicability for most real-world microwave signal-processing applications. In this paper,we build highly efficient and wideband microwaveto-photonic modulators using the acousto-optic effect on suspended lithium niobate thin films. A wideband microwave signal is first piezoelectrically transduced using interdigitated electrodes into Lamb acoustic waves,which directly propagates across an optical waveguide and causes refractive index pertp urbation through the photoelastic effect. This approach is power-efficient,with phase shifts up to 0.0166 rad∕m W over a 45μm modulation length and with a bandwidth up to 140 MHz at a center frequency of 1.9 GHz. Compared to the state-ofthe-art,a 9×more efficient modulation has been achieved by optimizing the acoustic and optical modes and their interactions.