基于铌酸锂薄膜波导和微结构电极的高速光束偏转研究

Optical beam deflection based on electro-optic effect due to its high-speed modulation characteristics leads to immense applications in the domains such as high-speed optical switch and signal processing, electro-optic sampling and scanning in ultra-fast optics, beam smoothing for high-intensity laser and optical manipulation in biophotonics. The current optical beam deflectors made by electro-optic material need high driving-voltage and the dimensions are not integratable, which cannot attain to high-speed operation. According to our previous researches on electro-optic modulation in micro and nanostructured lithium niobate waveguide, this project innovatively merges the optical waveguide technique in lithium niobate thin film and the non-coplanar microstructured electrodes for high-speed modulation to surmount the current scientific and technique bottleneck. The key scientific issues of mode deflection of optical waveguide based on the manipulation of refractive index distribution and its high-speed modulation will be studied, the feasibility towards on the integration of optical waveguide deflector will also be concerned. The relevant sciences and technologies for the miniaturization (length<200 microns), high-speed modulation (GHz) and low driving voltage (<10V) of the beam deflector will be involved. The research content includes the hybrid waveguide of lithium niobate thin film based on ridge and proton exchange techniques, the non-coplanar microstructured electrodes to electrically manipulate the distribution of refractive index variation in waveguide and simultaneously to realize high-speed optical beam deflection, the optimization theory for the overlap interaction of electro-optic field between transmitted light and electric field of the microstructured electrodes, etc., so as to realize the integratable high-speed optical beam deflector.

基于电光效应的光束偏转由于其高速调制性使其在高速光交换与信息处理、超快光学的电光采样与扫描、高能激光束匀滑和生物光子操控等领域具有难以估量的应用。目前电光材料的光束偏转器件所需驱动电压较大、尺寸难以集成、达不到高速化要求。本项目根据在微纳结构铌酸锂波导电光调制的研究基础，创新性地融合新型铌酸锂薄膜光波导技术和适应于高速调制的非共面微结构电极，突破目前的科技瓶颈，探索实现基于波导折射率分布电调控的光束偏转和高速调制的关键科学问题，研究可用于集成的新型光束偏转器件的可行性。解决光束偏转器件的微型化(长度<200微米)、高速化（GHz）和低驱动电压（<10V）等科学和技术问题。研究内容包括基于脊型和质子交换技术的铌酸锂薄膜混合波导、非共面微结构电极同时实现波导折射率空间变化的电调控和光束高速偏转的创新科学机理、传输光与微结构电极的电场分布相互交叠的电光优化理论等，实现可用于集成的高速光束偏转器。

基于电光效应的光束偏转由于其高速调制性使其在高速光交换与信息处理、超快光学的电光采样与扫描、高能激光束匀滑和生物光子操控等领域具有难以估量的应用。目前电光材料的光束偏转器件所需驱动电压较大、尺寸难以集成、达不到高速化要求。本项目根据在微纳结构铌酸锂波导电光调制的研究基础，创新性地融合新型铌酸锂光波导技术和适应于高速调制的微结构电极，突破目前的科技瓶颈，探索实现基于波导折射率分布电调控的光束偏转和高速调制的关键科学问题，研究可用于集成的新型光束偏转器件的可行性。解决了光束偏转器件的微型化、高速化和低驱动电压等科学和技术问题。研究内容包括基于铌酸锂混合波导、微结构电极同时实现波导折射率空间变化的电调控和光束高速偏转的创新科学机理、传输光与微结构电极的电场分布相互交叠的电光优化理论等。其具体实现结果如下：...1)理论上建立了混合波导和微结构电极的研究模型，掌握了微结构电极的电场和铌酸锂混合波导传输光的相互作用和光束偏转机理，获得了电极的电场和传输光的交叠分布如何影响有效电光系数并建立一套适用于铌酸锂薄膜微型化光子器件的设计方法，进而实现光束偏转器件工作作用长度小于200微米；.2）实现光束偏转高速调制的关键科学机理，设计并优化器件的非共面微结构电极，使光束偏转器件适应于高速化实现了大于GHz的偏转速率，所需的驱动电压小于10V，实现偏转角度6.2度；.3）在实现器件的制备和品质保证的同时，降低器件的损耗（插入损耗小于5dB），实现器件的可集成性和实效性。