● 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 leading research fellow at International Quantum Academy and Hefei National Laboratory, 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; Master of Science "mit Auszeichnung bestanden (with highest distinction)”from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) in Germany in 2016. In 2020, he received Ph.D. from EPFL in Switzerland under the supervision of Prof. Tobias J. Kippenberg. 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 returned to China and has established his independent research group since then. His  research  interest spans over integrated photonics, quantum optics and quantum information, microwave photonics, MEMS and laser spectroscopy. He has published more than 80 articles in peer-review journals, including 7 Nature, 3 Science, 6 Nature Photonics / Physics, 16 Nature Communications, 3 Science Advances, 3 Light: Science & Applications, 5 Optica, 3 Phys. Rev. Lett. / Phys. Rev. X. He is currently an Associated Editor of Phys. Rev. Applied of American Physical Society.