报告题目：Efficient Octave Spanning Super-continuum Generation from Ta₂O₅ based Nonlinear Waveguide

报告人：李晁逵，台湾中山大学（高雄）光电工程学系，教授

报告时间：2019年3月21日（周四） 下午16:30

报告地点：米兰·(MILAN)官方网站,逸夫科学楼A208

简介：李晁逵 （Chao-Kuei Lee），台湾中山大学（高雄）光电工程学系教授。2003年在台湾交通大学（新竹）获得博士学位， 2004年起，任教于台湾中山大学（高雄），担任光电工程学系飞秒与量子调控实验室负责人，是物理系双聘教授。主要从事超快量子电子学、二维材料、拓扑绝缘体、非线性光学、太赫兹光学的研究。主要研究方向是（1）利用脉冲激光技术，产生和表征超快光子信号，（2）太赫兹光子学，（3）二维材料的动态性质以及应用，（4）可用于硅基光子学和宽频带的相干光源，（5）非线性光波导的构筑和表征。在Science、Nature子刊等期刊发表SCI论文70余篇，平均每篇引用次数超过10。

摘要:   To achieve high bit rate signal processing in the integrated optical system, the ultrafast all optical modulator is regarded as the key element in the modern optical communication system. Up to date, number of material systems, such as Si, SiO, SiN and so on, have been chosen for nonlinear optical processing in waveguide photonics fields. However, the physical limitation on application is on the inevitable linear or nonlinear absorption performance. Recently, a low-loss and high-Q Ta₂O₅ based micro-ring resonator is developed and presented. The micro-ring resonator and channel waveguide with core area of the 700 by 400 nm² were fabricated on amorphous Ta2O5 thin films prepared by reactive sputtering with Q as high as 2x10⁵. Meanwhile, the nonlinear refractive index of Ta2O5 waveguide at 1550 nm as high as 4 × 10⁻¹⁴ cm²∕W was also reported. In this work, the progress of nonlinear optical properties of low loss waveguide based on Tantalum Pentoxide (Ta₂O₅) will be introduced. The anomalous dispersion Ta₂O₅ based waveguide was designed and fabricated for super-continuum generation(SCG) due to its nature of two photon absorption free and high optical nonlinearity. The measurements show that SCG ranging from 585 to 1697 nm (at -30 dB) is obtained at a pumping wavelength of 1056 nm and the spectrum broadens at least 1.5 octaves. The pumping power of the aforementioned spanning result is 396 W, much lower than other materials for achieving the same SCG result that had been reported. In addition, the SCG from high order mode waveguide will be discussed as well.

Keywords：   Ta₂O₅, Nonlinear waveguide, Super continuum