● The development and optimization of the "photonic Damascene process ", a novel but mature CMOS nanofabri-

   cation technology for Si3N4 PIC which enables 90% fabrication yield and ultralow optical losses of only 0.5 dB/m

   – currently the world lowest value found in any tight-optical-confinement PIC. [Nat. Commun. 12, 2236 (2021)].

● The first demonstration of coherent soliton microcombs of 10 and 20 GHz repetition rates in Si3N4, which could 

   have  critical  impact for high-spectral-efficiency  coherent  optical  communications  and  low-noise  microwave

   synthesis. [Nat. Photon. 14, 486 (2020)].

● The first demonstration of hybrid integration of DFB laser chips with Si3N4 chips, which enables the so-far most-

   compact and smallest microcomb modules operated at CMOS frequencies. [Nature 582, 365 (2020)].

● The first demonstration of wafer-scale heterogeneous integration of InP/silicon lasers on ultralow-loss Si3N4 PIC

   –a decade-long standing goal pursued by the entire communities of integrated photonics and frequency combs.

   [Science 373, 99 (2021)].

● The  first  demonstration of monolithically  integrated acousto-optic  modulators  on Si3N4 using  MEMS-based

   piezoelectric  aluminum nitride , for  applications  such as  coherent  LiDAR  and  magnetic-free  on-chip  optical 

   isolators. [Nature 583, 385 (2020)] & [Nat. Photon. 15, 828 (2021)].

● The  first observation of backward  stimulated Brillouin scattering  (SBS)  in Si3N4. [Phys. Rev. Lett. 124, 013902

   (2020)].  

● The ultralow-loss Si3N4 chips fabricated by him have been also used in several system-level applications such as

   astronomical spectrometer calibration, massively parallel coherent LiDAR, mid-infrared dual-comb spectroscopy,

   photonic neuromorphic computing,optical coherent tomography,photonic microwave filters, datacenter ultrafast

   circuit switches, narrow-linewidth lasers, erbium-doped waveguide amplifiers, travelling-wave parametric amplif-

   iers, and ultrafast electron transmission spectroscopy.

Prof. Junqiu Liu  is currently a research fellow at International Quantum Academy  / Hefei National Laboratory of Quantum Information Science, and a tenure-track assistant professor at the University of Science and Technology of China (USTC).  He received Bachelor of Science from USTC in 2012. In 2016 he received Master of Science " mit Auszeichnung bestanden (with highest distinction) ” from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) in Germany. In 2020, he received Ph.D. from EPFL in Switzerland under the supervision of Prof. Tobias J. Kip-penberg. His doctoral thesis entitled "Silicon Nitride Integrated Nonlinear Photonics" won the 2021 EPFL Doctoral Prize ,  " for ground breaking experiments in the field of chip-scale frequency combs and the extraord-inary record of scientific accomplishments". After his postdoctoral research stay at EPFL till December 2021, he retur-ned to China and has established his independent research group since then.

His  research  has addressed multiple  central  topics in the development of chip-based microcombs and  narrow-linewidth  heterogeneous lasers  using  CMOS  nanofabrication  technology, and  applied  them  for  applications   including inertial sensors  , telecommunications, photonic  computing , and laser spectroscopy. He has published more than 60 articles in peer-review journals, including 7 Nature,3 Science, 6 Nature Photonics/Physics, 15 Nature Communications, 3 Science Advances, 5 Optica, 2 PRL / PRX. Key achievements of him are following: