Prof.  Qingzhong  Huang
Huazhong University of Science and Technology (HUST),  China

Title: Integrated optical microresonators for filtering, buffering, and switching applications

Abstract:

Owning to the compact size, wavelength selectivity and flexibility, optical microresonators (e.g. microring resonator, microdisk resonator, Fabry-Perot resonator) have become the key building blocks for various integrated photonic devices, which are widely applicable for optical filtering, buffering, and switching. Using a single microdisk resonator (MDR) in silicon, we experimentally demonstrated a dual-band optical filter with low insertion loss and high optical isolation (>20dB). We also show that the waveguide-coupled multimode resonator (i.e. MDR, microdonut) can exhibit either a flat-top response for filtering or all-passtransmission for buffering, by engineering the dual resonances in the resonators. Electromagnetically induced transparency (EIT) has attracted considerable attentions recently due to its wide applications in slowing or stopping light. We observed EIT-like resonance in an ultra-compact two-bus waveguides coupled MDR of 3 μm in radius with a quality factor of 4200. Then, we have obtained EIT and electromagnetically induced absorption phenomena in a compact silicon ring-bus-ring-bus system (~22 μm × 11 μm). Furthermore, we investigated the plasmon-induced transparency and slow-light properties in a plasmonic single-mode and two-mode resonators coupled system. A delay-bandwidth product larger than 1 and ultralow dispersion are obtained, and a delay of 1 bit with negligible pulse distortion is achieved. To construct optical switches, we have proposed and realized a novel channel add-drop filter based on a single Fabry–Perot resonator, behaving like a traveling-wave resonator where fields are coupled to the buses in one direction. Silicon thermo-optic switch based on such a resonator is realized with an insertion loss of 0.8dB, crosstalk of -8dB, and switching time of < 8μs. 

Biography:

Qingzhong Huang received the B.S. degree from Zhejiang University, China, in 2004, and received the Ph.D. degree from Institute of Semiconductors, Chinese Academy of Science, in 2009. Then, he joined Huazhong University of Science and Technology (HUST), China. Currently, he is an associate professor in Wuhan National Laboratory for Optoelectronics, HUST. His research interests include integrated photonics, silicon photonics, optical interconnect, optical communications, and micro/nanofabrication techniques. He has published over 50 peer-reviewed journal papers and over 10 conference papers. He is a member of OSA and IEEE. He also serves as a scientific referee for over 10 prestigious journals and referee of proposal for National Natural Science Foundation of China.