题 目：Photonics Quantum Processing using Frequency and Time
报告人：Roberto Morandotti
单 位：Department of the Institut National de la Recherche Scientifique, Canada
主持人：曾和平 教授
时 间：11月21日（周五）下午15:00-15:40
地 点：光学大楼A508会议室
报告内容简介：
Encoding quantum information into photon states provides the tools to make quantum technologies, such as quantum sensing, metrology, and communication, compatible with currently available infrastructures like integrated devices and optical fibers. Photons offer a wide variety of degrees of freedom, including orbital angular momentum, spatial, frequency, and time modes, to encode and access high-dimensional quantum information in the form of d-level (or qudit) states. Qudits offer several advantages over qubits for quantum technologies. For instance, qudits are more resilient to noise and loss, enabling higher quantum information processing speeds and security levels. In this regard, encoding quantum information in the time of arrival of a photon (i.e., in the time-bin) is a versatile approach for processing quantum information in on-chip and telecom-fibre architectures [3,4], as well as for scaling up the qudit dimensionality while keeping low-footprint platforms. Such a scaling up critically necessitates interferometric schemes capable of processing time-bin qudits with high phase stability, timing accuracy, and fast switches. We have recently demonstrated the generation and phase-stable processing of time-bin entangled photon states via two different interferometric schemes. The first scheme comprises a cascade of on-chip unbalanced interferometers and an integrated spiral waveguide serving as an entanglement source, enabling the realization and processing of picosecond-spaced time-bin entangled photonic qudits over the telecom C band. We utilize this platform to implement the first entanglement-based quantum key distribution protocol via entangled qudits and extend it over a 60-km-long optical fiber link. We demonstrate secret key rates in the order of few kbit/s, orders of magnitude higher than those achievable via entangled qubits. The second scheme comprises a fully fibered coupled-loop system (used as an unbalanced interferometer) and two periodically poled lithium niobate waveguides as an entanglement source. This platform enables the implementation of a synthetic temporal photonic lattice, which we exploit for the generation and controlled processing of time-bin entangled states. We show that controlled quantum walks lead to coincidence counts enhancement and post-selection-free quantum interference measurements. O devices together with standard telecom coding schemes and equalization techniques.
报告人简介：
Roberto Morandotti (Professor and Group Leader in the Energy Materials Telecommunications Department of the Institut National de la Recherche Scientifique) received his M.Sc. degree in physics from the University of Genova, Genova, Italy, in 1993, and his Ph.D. degree from the University of Glasgow, Glasgow, U.K., in 1999. Since 2003, he has been with INRS-EMT, Varennes, Canada.
His current research interests include integrated optics for quantum and machine learning applications, as well as Terahertz science and applications.
Roberto Morandotti is a Tier 1 Canada Research Chair (2016-2030), a Fellow of the Royal Society of Canada, of the AAAS, of the IEEE, of the APS, of the Optica, of the SPIE, and an E.W.R Steacie Memorial Fellow (2011), a recipient of the NSERC Synergy (2019) and Brockhouse (2020) Awards, of the Prix Marie-Victorin (2022) and the Prix Urgel-Archambault (2023) of Quebec, of the Leadership in Research Award of the University of Quebec (2024), as well as of the IEEE Quantum Electronics Award (2025), among others. He served as a Chair and Technical Committee Member for several Optica, IEEE, and SPIE-sponsored meetings. He was recognized as an exceptional Mentor by the Canadian Association for Graduate Students (2018) and by the INRS (2024)