Graphene based electro-optic modulators and thermo-optic switches

Speaker:    Prof. Ciyuan Qiu

Time:         16:00-17:00  Sept.24.2021

Location:   SIST 1A 200

Host:          Prof. Pingqiang Zhou

Abstract:   Recently, graphene has been used to build various optical devices, by using its high carrier mobility and high thermal conductivity. In this talk, I will present our works on graphene-based integrated photonic devices, including electro-optic modulators and thermo-optic switches. Firstly, I will show a graphene-silicon hybrid micro-ring modulator and a nanobeam modulator. Such modulators can have a very high modulation speed (tens of GHz) and a high modulation efficiency. Then, I will talk about an all-optical graphene-Si₃N₄ switch. A response time constant of 253.0 ns and a switching energy of ~50 nJ are obtained. Finally, I will show a tunable optical filter/switch based on a nanobeam resonator. In this switch, a tuning efficiency of ~1.5 nm/mW is achieved by using a graphene micro-heater.

Bio:   Dr. Ciyuan Qiu is currently an associate professor in Shanghai Jiao Tong University. He received the B.S. degree and M.S. degree from Tsinghua University, Beijing, China in 2005 and 2007 respectively, and the Ph.D. degree from Rice University, Houston, Texas, in 2013. He then worked as post-doc in Rice University until June 2014. He joined Shanghai Jiao Tong University, Shanghai, China, in August 2014. Dr. Qiu has published over 65 journal and conference papers, such as Nano Letters, Optics Letters and Optics Express. His research interests include Silicon Photonics Devices and Circuit, Graphene Optics and Plasmonics.