Publications by Ozan Yakar | EPFL Graph Search

Self-organized spatiotemporal quasi-phase-matching in microresonators

Camille Sophie Brès, Jianqi Hu, Anton Stroganov, Ozan Yakar, Ji Zhou, Edgars Nitiss, Marco Clementi

Quasi-phase-matching (QPM) is a widely adopted technique for mitigating stringent momentum conservation in nonlinear optical processes such as second-harmonic generation (SHG). It effectively compensates for the phase velocity mismatch between optical harm ...

Springer Science and Business Media LLC2025

Dissipative Kerr soliton generation at 2μm in a silicon nitride microresonator

Camille Sophie Brès, Anton Stroganov, Ozan Yakar, Christian André Clément Lafforgue, Marco Clementi, Anamika Nair Karunakaran

Chip -scale optical frequency combs enable the generation of highly -coherent pulsed light at gigahertz-level repetition rates, with potential technological impact ranging from telecommunications to sensing and spectroscopy. In combination with techniques ...

Optica Publishing Group2024

Spatiotemporal Quasi-Phase-Matching in Microresonators

Camille Sophie Brès, Jianqi Hu, Ozan Yakar, Ji Zhou, Edgars Nitiss, Marco Clementi

We show how spatiotemporal quasi-phase-matching emerges from all-optical poling of silicon nitride microresonators. Enabled by the coherent photogalvanic effect, the photoinduced χ(2) grating oscillates in space and time, yielding quasi-phase-matched and D ...

Institute of Electrical and Electronics Engineers Inc.2024

Photoinduced Second-Order Nonlinearities in Centrosymmetric Media

Ozan Yakar

The interaction of light and matter enables nonlinear frequency conversion and the creation of coherent currents. The optical control of electric currents is of fundamental relevance and prominent research focus in the last decades. These photocurrents ena ...

EPFL2024

Integrated Backward Second-Harmonic Generation through Optically Induced Quasi-Phase-Matching

Camille Sophie Brès, Jianqi Hu, Ozan Yakar, Edgars Nitiss

Quasi-phase-matching for efficient backward second-harmonic generation requires sub-μm poling periods, a nontrivial fabrication feat. For the first time, we report integrated first-order quasiphase-matched backward second-harmonic generation enabled by see ...

2023

Mid-IR Soliton Microcomb Generation in Silicon Nitride Microring Resonators

Camille Sophie Brès, Ozan Yakar, Christian André Clément Lafforgue, Marco Clementi

We demonstrate soliton Kerr-comb generation in a high-Q silicon nitride microring with 143 GHz free spectral range pumped at 1970 nm. The resulting low noise ultrafast pulse train displays a 422 nm bandwidth, extending up to 2250 nm. ...

2023

Photo-induced cascaded harmonic and comb generation in silicon nitride microresonators

Tobias Kippenberg, Camille Sophie Brès, Jianqi Hu, Ozan Yakar, Junqiu Liu, Wenle Weng, Jijun He, Edgars Nitiss

Silicon nitride (Si3N4) is an ever-maturing integrated platform for nonlinear optics but mostly considered for third-order [chi(3)] nonlinear interactions. Recently, second-order [chi(2)] nonlinearity was introduced into Si3N4 via the photogalvanic effect, ...

2022

Generalized Coherent Photogalvanic Effect in Coherently Seeded Waveguides

Camille Sophie Brès, Jianqi Hu, Ozan Yakar, Edgars Nitiss

The coherent photogalvanic effect leads to the generation of a current under the absorption interference of coherent beams and allows for the inscription of space-charge gratings leading to a second-order susceptibility (chi((2))). The inscribed grating au ...

2022

Backward Second-Harmonic Generation in Optically Poled Silicon Nitride Waveguides

Camille Sophie Brès, Jianqi Hu, Ozan Yakar, Edgars Nitiss

We report the inscription of quasi-phase-matching gratings in silicon nitride waveguides for backward second-harmonic-generation enabled by all-optical poling, therefore, circumventing the difficulties in inscribing poled domains with ultra-short periods. ...

2022

Difference-frequency generation in optically poled silicon nitride waveguides

Tobias Kippenberg, Camille Sophie Brès, Rui Ning Wang, Ozan Yakar, Boris Zabelich, Junqiu Liu, Edgars Nitiss, Ezgi Sahin

Difference-frequency generation (DFG) is elemental for nonlinear parametric processes such as optical parametric oscillation and is instrumental for generating coherent light at long wavelengths, especially in the middle infrared. Second-order nonlinear fr ...

WALTER DE GRUYTER GMBH2021