PHOSL has achieved several important milestones in exploiting the rich physics offered by microresonators. Our interest lie in leveraging the advances in the maturing fabrication of high Q microresonators, which opens new possibilities in terms of 1) pushing optical nonlinear interactions to new regimes, 2) expanding the operating wavelengths, 3) develop the physics based on novel observations.
For example, we are investigation how to to all-optically utilize the internal soliton states of microresonators to perform RF photonic filters without any additional pulse shaping. We also demonstrated all-optical reconfigurability of the filters by deterministically accessing diverse internal two-soliton states. Recently we also achieved the first optically induced quasi-phase matching in silicon nitride microresonator and are looking into developing the physics of this intriguing phenomenon and how to increase efficiencies. Our current work already shows that silicon nitride microresonators can efficiently generate second harmonic light with an ultra-broad bandwidth unparalleled by most other microresonators, even in platforms with native 2nd order nonlinearities. While optical poling results in periodic nonlinearity perfectly suited for phase matching three wave mixing processes, we recently showed that thermally assisted electric-field poling gives rise to a constant electric field perfectly suited for electro-optical modulation. Interestingly these optically induced nonlinearities open opportunities for coupled 2nd/3rd order nonlinear effects and further expands the potential of microresonators.
Selected Publications:
1. E. Nitiss, B. Zabelich, J. Hu, A. Stroganov, C.-S. Brès, ‘Silicon nitride electric-field poled microresonator modulator,’ APL Photonics 9, 016101 (2024)
2. J. Hu, E. Nitiss, J. He, J. Liu, O .Yakar, W. Weng, T.J .Kippenberg, C.-S. Brès, ‘Photo-induced cascaded harmonic and comb generation in silicon nitride microresonators,’ Science Advances 8 (50), eadd8252 (2023)
3. E. Nitiss, J. Hu, A. Stroganov, C.-S. Brès, ‘Optically reconfigurable quasi-phase-matching in silicon nitride microresonators,’ Nature Photonics, 16, pp. 134–141, (2022)
4. J. Hu, J. He, J. Liu, A.S. Raja, M. Karpov, A. Lukashchuk, T.J. Kippenberg, C.-S. Brès, ‘Reconfigurable radiofrequency filters based on versatile soliton microcombs,’ Nature Communications 11(1), pp. 1-9 (2020)