主题：Novel material of nonlinear waveguide for Si photonics: from light source to all optical modulation
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. For example, Si has only a finite transparency range, restricting its usage in the visible region. Furthermore, Si suffers from significant two-photon as well as free-carrier absorption due to low band gap structure, greatly suppressing the nonlinear optical property, and hence the nonlinear optical application in Si photonics. On the other hand, low nonlinear coefficient in SiO2 and high stress on depositing thick Si3N4 film has posed material limitation on applications. As a result, seeking high-nonlinearity material while maintaining low absorption is always an important issue to enable all-optical photonics. Recently, a low-loss and high-Q Ta2O5 based micro-ring resonator is 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 2×105. 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 linear and nonlinear optical properties of low loss waveguide based on Tantalum Pentoxide (Ta2O5) and its application for Si photonics (from FWM-OPO to ten GHz all optical modulation) will be discussed.
Chao-Kuei Lee received his PhD degree of Electro-Optical engineering from National Chiao Tung University, Taiwan, in 2003. Prof. Lee joined National Sun Yat-sen University (高雄中山大學) in 2004. He is currently full professor who directs the laboratory of Femtosecond & Quantum Modulation with the Department of Photonics. Now, He is conjointly appointed by Department of Physics of National Sun Yat-sen University and research center of applied science (RCAS) of academic sinica. His research interests focus on ultrafast photonics, including generating and characterizing ultrafast photonic signals with pulse shaping technique, THz Photonics, dynamic properties and applications of two dimensional materials, and nonlinear waveguide fabrication and applications for Si photonics and broadband coherent light source. Dr. Lee has published more than 40 reviewed journal papers, including five science or nature series papers, since 2011. The average citation number per paper is more than 10.