USTC realizes waveguide mode-encoded quantum logic gate for the first time
The team of Academician Guo Guangcan from the University of Science and Technology of China has made important progress in the research of optical quantum chips. The team, Ren Xifeng's research group, cooperated with Dai Daozin's team from the School of Optoelectronic Science and Engineering of Zhejiang University/State Key Laboratory of Modern Optical Instruments, and realized the first two-bit quantum logic gate operation of on-chip waveguide mode coding in the world. The related results were published on February 11. Published in the internationally renowned academic journal "Physical Review Letters".
Both classical and quantum information applications require a substantial increase in the information processing and communication capabilities of photonic chips to meet the growing demand for optical communication and interconnection. In order to realize large-scale optical quantum systems, multi-photon, multi-degree-of-freedom and high-dimensional encoding are inevitable approaches. The unique properties of multimode waveguide modes, such as high-dimensional expansion, compactness, and arbitrary coherent conversion with other degrees of freedom, make waveguide mode coding promising in the field of integrated photonics. Therefore, waveguide mode coding has attracted much attention in recent years.
Ren Xifeng's research group and Dai Daozin's team of Zhejiang University have long-term cooperation in the research of silicon-based optical quantum devices and chips, and have made a series of important progress: (1) For the first time in the world, the waveguide mode encoding is used for quantum information processing, and the waveguide mode, polarization and Coherent conversion between path-encoded entangled states (Nat Commun 7, 11985, 2016); (2) First realization of waveguide mode-encoded entangled light source preparation (npj Quantum Inf 5, 2, 2019); (3) Dense waveguide based superlattice The array constructs the world's smallest size optical quantum controlled NOT gate (Phys Rev Lett. 126.130501 (2021)), etc. On this basis, the two parties further cooperated to independently design and develop two new multi-mode photonic devices, such as waveguide mode coupler (TMDDC) and mode attenuator (MMA), which are used to achieve specific mode-dependent coupling and mode-dependent attenuation, etc. and further integrated these novel photonic functional devices monolithically, demonstrating for the first time in the world the two-bit controlled non-gated operation of waveguide mode coding.
Figure 1. Schematic diagram of photonic waveguide mode-encoded quantum-controlled NOT gate chip
This achievement paves the way for waveguide mode-encoded quantum operations, which can also be used for on-chip multi-degree-of-freedom optical quantum information processing. The reviewers agreed that this is an important research work and gave high evaluations: "The two new components TMDDC and MMA invented here are important", "I believe that the work presented in this letter will provide essential tools in that field".
Professor Ren Xifeng from the Key Laboratory of Quantum Information of the Chinese Academy of Sciences, Professor Dai Daozin from the School of Optoelectronic Science and Engineering of Zhejiang University/State Key Laboratory of Modern Optical Instruments are the co-corresponding authors of the paper, Feng Lantian, a special associate researcher of the Key Laboratory of Quantum Information of the Chinese Academy of Sciences, and an assistant researcher of Zhejiang University Zhang Ming is the co-first author of the paper. This work was funded by the Ministry of Science and Technology, the National Foundation of China, the Chinese Academy of Sciences, Anhui Province, and the University of Science and Technology of China.
Paper link:https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.060501
