Plenary Speakers

DATE: 5/13/2020

Explorations of topological photonics in synthetic dimensions

Shanhui Fan

Stanford University, USA

    Abstract: The demonstrations of non-trivial topological effects in photonics have greatly enriched the study of fundamental optical physics, and may lead to optical devices that are robust against disorders and perturbations. The initial explorations of topological photonics have largely been restricted in the study of effects in real physical space, where non-trivial topology arises in complex photonic structures. In recent years, there have been emerging interests in exploring synthetic dimensions, which provides far more versatile platforms for exploring topological photonics. In this talk, we review some of our recent theoretical and experimental efforts in exploring frequency synthetic dimensions. When a ring resonator undergoes dynamic refractive index modulation, the modes of in the resonator can couple to form a synthetic lattice along the frequency dimension. In this system, the Hamiltonian of the system is controlled by the modulation format, which provides tremendous flexibilities for exploring novel physics. We show that a band structure along the synthetic dimension can be characterized by a time-domain measurement. Using such band structure spectroscopy technique, we experimentally demonstrate a wide range of topological effects, including synthetic magnetic field for photons in Hermitian systems, as well as band winding and band braiding in non-Hermitian systems.

  Biography: Shanhui Fan is a Professor of Electrical Engineering, a Professor of Applied Physics (by courtesy), a Senior Fellow of the Precourt Institute for Energy, and the Director of the Edward L. Ginzton Laboratory, at the Stanford University. He received his Ph. D in 1997 in theoretical condensed matter physics from the Massachusetts Institute of Technology (MIT). His research interests are in fundamental studies of solid state and photonic structures and devices, especially photonic crystals, plasmonics, and meta-materials, and applications of these structures in energy and information technology applications. He has published approximately 600 refereed journal articles, has given over 380 plenary/keynote/invited talks, and was granted 69 US patents. His publications have been cited over 90,000 times according to Google Scholar. He has cofounded two companies aiming to commercialize high-speed engineering computations as well as radiative cooling technology respectively.  Prof. Fan received a National Science Foundation Career Award (2002), a David and Lucile Packard Fellowship in Science and Engineering (2003), the National Academy of Sciences W. O. Baker Award for Initiative in Research (2007), the Adolph Lomb Medal from the Optical Society of America (2007), a Vannevar Bush Faculty Fellowship from the U. S. Department of Defense (2017), and a Simons Investigator in Physics (2021).  He is a Thomson Reuters Highly Cited Researcher in Physics since 2015,  and a Fellow of the IEEE, the American Physical Society, the Optical Society of America,  and the SPIE.

Emerging Optical and Photonic Technologies for Communications and Beyond

Xiang Liu

Huawei Hong Kong Research Center, China

    Abstract:The journey leading to the era of the 5th generation mobile and fixed networks, 5G and F5G, has witnessed ground-breaking innovations in optical communications and photonics. For the journey ahead, we are facing two grand technical challenges, the communication capacity limit imposed by the Shannon theorem and the slowing down of the Moore’s law. To address the impact of the Shannon capacity limit, the optical communications community is exploring innovative network architectures, system designs, photonic integrated circuits, and better integration of photonic and electrical circuits to continue reducing the cost and energy consumption per bit. To address the impact of the noticeable slowing down of the Moore’s law, the photonics community is exploring innovative algorithms, software, application-specific designs, advanced fabrication processes, and new material platforms via a holistic approach. In parallel, the communications and photonics communities are also broadening the application space of the optical and photonic technologies to new fields such as 3D sensing for consumer devices, head-up display, light detection and ranging for autonomous driving, distributed fiber-optic sensing, and optical computing. In this talk, we review emerging optical and photonic technologies for meeting the ever-increasing demands of communications, as well as addressing new applications beyond communications.

   Biography: Xiang Liu is chief optical standards expert at Huawei Technologies. He has more than 20 years of working experience in the optical communication industry. He had served as Vice President for Optical Transport and Access at Futurewei Technologies, focusing on optical technologies, standards, and industry development for optical transport and access networks. Before joining Futurewei, he had been with Bell Labs working on high-speed optical transmission technologies for 14 years. He has authored over 350 publications and holds over 100 US patents.
      Xiang received the Ph.D. degree in applied physics from Cornell University in 2000. He is a Fellow of the IEEE, a Fellow of the OSA, a Deputy Editor of Optics Express, an Advisory Board member of NGOF, and a steering committee member of ACP. Xiang has served as a Technical Program Co-Chair of OFC 2016, and a General Co-Chair of OFC 2018.

Photonic Chip based Frequency Combs

Tobias J. Kippenberg

EPFL, Switzerland

    Abstract:The development of optical frequency combs1, and notably self-referencing, has revolutionized precision measurements over the past decade, and enabled counting of the cycles of light. Frequency combs, have enabled dramatic advances in timekeeping, metrology and spectroscopy. In 2007, it was discovered that such combs can also be generated using an optical microresonator2 using parametric frequency conversion. Importantly, such Kerr combs also enable to generate dissipative temporal solitons (DKS)3,4, which are formally solutions to a driven dissipative nonlinear Schrödinger equation, termed Lugiato-Lefever equation – first derived to describe spatial self-organization phenomena5. DKS have unlocked the full potential of Kerr combs enabling a deterministic route to broadband, and coherent optical frequency combs, whose bandwidth can be enhanced using soliton broadening phenomena, such as Soliton Cherenkov Radiation6. Such Solitons Kerr combs on a chip have enabled to realize counting of the cycles of light, realize dual comb spectrometers on a chip, enabled dual comb based ultrafast ranging7, massively parallel coherent communication8, and offered a novel approach to massively parallel FCMW LiDAR9. Recent advances based on the photonic damascene process10 enable ultra low loss nonlinear photonic circuits based on silicon nitride (Si3N4), have enabled ultra-low losses, and direct integration with on chip pump lasers11.

   Biography: Tobias J. Kippenberg is Full Professor in the Institute of Physics and Electrical Engineering at EPFL in Switzerland since 2013 and joined EPFL in 2008 as Tenure Track Assistant Professor. Prior to EPFL, he was Independent Max Planck Junior Research group leader at the Max Planck Institute of Quantum Optics in Garching, Germany. While at the MPQ he demonstrated radiation pressure cooling of optical micro-resonators, and developed techniques with which mechanical oscillators can be cooled, measured and manipulated in the quantum regime that are now part of the research field of Cavity Quantum Optomechanics. Moreover, his group discovered the generation of optical frequency combs using high Q micro-resonators, a principle known now as micro-combs or Kerr combs.

For his early contributions in these two research fields, he has been recipient of the EFTF Award for Young Scientists (2011), The Helmholtz Prize in Metrology (2009), the EPS Fresnel Prize (2009), ICO Award (2014), Swiss Latsis Prize (2015), as well as the Wilhelmy Klung Research Prize in Physics (2015) and the 2018 ZEISS Research Award. Moreover, he is 1st prize recipient of the "8th European Union Contest for Young Scientists" in 1996 and is listed in the Highly Cited Researchers List of 1% most cited Physicists in 2014-2019. He is founder of the startup LIGENTEC SA, an integrated photonics foundry.

The free-electron laser based on a laser accelarator

Ruxin Li

ShanghaiTech University, China

    Abstract:Free electron lasers (FELs) are capable of generating intense and coherent radiation at X-ray spectral region and have become indispensable tools for various applications. Several X-ray FEL facilities have been successfully operated which rely on the state-of-the-art radio-frequency accelerators with enormous size and cost. Great interest has been drawn to the development of more compact and economical accelerators. The laser wakefield accelerator (LWFA) is an attractive approach for its capability of sustaining accelerating gradient three orders of magnitude higher than that of radio-frequency accelerators and is regarded as a revolutionary solution for driving future compact FELs. However, the realization of such kind of compact FELs still remains a challenge due to the relatively poor beam quality of electrons based on an LWFA. Here we show the experimental demonstration of the undulator radiation amplification in the exponential gain regime using LWFA-based electron beams, typically centered at the wavelength of 27 nm. Our results constitute the first unambiguous proof-of-principle demonstration of the free electron lasing with an LWFA and pave the approach towards LWFA-based compact FELs with broad interests.

Biography: Prof. Ruxin Li is a professor in Physics of Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences and ShanghaiTech University. He was elected as the OSA Fellow in 2014 and elected as the academician of Chinese Academy of Sciences in 2017. He is the vice chairman of the Chinese Optical Society and he was the chairman of the Asian Intense Laser Network during 2010-2014. He is the committee member of the International Committee on Ultra-Intense Lasers (ICUIL). His research interests lie in the development of petawatt level high peak power ultrafast lasers, laser wakefield acceleration of electrons, high order harmonic generation in atoms and molecules, and femtosecond laser filamentation nonlinear optics.