Publications de Jianqi Hu | EPFL Graph Search

High-Energy Mode-Locked Pulses from a Photonic Integrated Mamyshev Oscillator

Tobias Kippenberg, Grigorii Likhachev, Jianqi Hu, Xinru Ji, Zheru Qiu, Zihan Li

Mode-locked lasers (MLLs), capable of generating ultrashort coherent pulses, have been instrumental for numerous applications, including optical frequency metrology, eye surgery, machining, additive manufacturing, imaging and spectroscopy. However, commerc ...

IEEE2025

Arrayed waveguide gratings in lithium tantalate integrated photonics

Tobias Kippenberg, Jianqi Hu

Arrayed waveguide gratings (AWGs) are widely used photonic components for splitting and combining different wavelengths of light. They play a key role in wavelength-division multiplexing (WDM) systems by enabling efficient routing of multiple data channels ...

Optica Publishing Group2025

Self-organized spatiotemporal quasi-phase-matching in microresonators

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

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

Twisted Talbot Effect: Self-Imaging in Angle and Orbital Angular Momentum

Jianqi Hu

The Talbot effect is a self-imaging phenomenon of periodic waves. In the last decades, the understanding of the self-imaging effect has been diversified to different degrees of freedom of different types of waves, highlighting its very general nature. Esse ...

IEEE2025

Arrayed Waveguide Gratings on Integrated Thin-Film Lithium Tantalate

Tobias Kippenberg, Jianqi Hu

Arrayed Waveguide Gratings (AWGs) are ubiquitous and efficient photonic devices used to split and combine different wavelengths of light. They have been widely used as (de)-multiplexer for wavelength division multiplexed optical communication systems, and ...

IEEE2025

Spatiotemporal Quasi-Phase-Matching in Microresonators

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

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

Azimuthal beam shaping in orbital angular momentum basis

Jianqi Hu

Shaping the light beam is always essential for laser technology and its applications. Among the shaping technologies, shaping the laser in its Fourier domain is a widely used and effective method, such as a pulse shaper, or a 4f system with a phase mask or ...

SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS2024

Broadband and turnkey Pockels micro-comb with Monolithic Microwave Resonator

Tobias Kippenberg, Jianqi Hu, Mikhail Churaev, Junyin Zhang

We demonstrate a fully hybrid integrated electrooptic comb generator based on a dispersion engineered thin-film Lithium Tantalate microresonator featuring robust turnkey operation and record-broad >200nm span covering the entire telecommunications S, C, an ...

Institute of Electrical and Electronics Engineers Inc.2024

Ultrabroadband Integrated Triply Resonant Electro-Optic Frequency Comb in Lithium Tantalate

Tobias Kippenberg, Jianqi Hu, Mikhail Churaev, Nikolai Kuznetsov, Zihan Li, Junyin Zhang

We demonstrated an integrated electro-optic frequency comb generator with 450nm span and 29.6GHz spacing, entirely covering optical telecom E-, S-, C-, L-, and U-bands, via monolithic co-integration of microwave and photonics resonators on thin-film lithiu ...

Optica Publishing Group (formerly OSA)2024

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

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

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

Bright and dark Talbot pulse trains on a chip

Camille Sophie Brès, Jianqi Hu, Edgars Nitiss, Jiaye Wu, Marco Clementi, Christian André Clément Lafforgue

Temporal Talbot effect, the intriguing phenomenon of the self-imaging of optical pulse trains, is extensively investigated using macroscopic components. However, the ability to manipulate pulse trains, either bright or dark, through the Talbot effect on in ...

Nature Portfolio2023

Tunable photo-induced second-harmonic generation in a mode-engineered silicon nitride microresonator

Camille Sophie Brès, Jianqi Hu, Anton Stroganov, Edgars Nitiss, Boris Zabelich

All-optical poling enables reconfigurable and efficient quasi-phase-matching for second-order parametric frequency conversion in silicon nitride integrated photonics. Here, we report broadly tunable milliwatt-level second-harmonic generation in a small fre ...

2023

Cost-effective equalization of electro-optic frequency combs in a Sagnac interferometer

Camille Sophie Brès, Jianqi Hu, Ivan Cardea

We present a cost-effective electro-optic frequency comb generation and equalization method using a single phase modulator inserted in a Sagnac interferometer layout. The equalization relies on the interference of comb lines generated in both clockwise and ...

Optica Publishing Group2023

Single-shot Kramers-Kronig complex orbital angular momentum spectrum retrieval

Camille Sophie Brès, Jianqi Hu, Yujie Chen

Orbital angular momentum (OAM) spectrum diagnosis is a fundamental building block for diverse OAM-based systems. Among others, the simple on-axis interferometric measurement can retrieve the amplitude and phase information of complex OAM spectra in a few s ...

SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS2023

Backward Second-Harmonic Generation in Optically Poled Silicon Nitride Waveguides

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

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

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

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

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

Temporal Talbot effect of optical dark pulse trains

Camille Sophie Brès, Jianqi Hu, Jiaye Wu

The temporal Talbot effect describes the periodic self-imaging of an optical pulse train along dispersive propagation. This is well studied in the context of bright pulse trains, where identical or multiplied pulse trains with uniform bright waveforms can ...

OPTICAL SOC AMER2022

Demonstration of Temporal Talbot Effect of Dark Pulse Trains

Camille Sophie Brès, Jianqi Hu, Jiaye Wu

2022

Generalized Coherent Photogalvanic Effect in Coherently Seeded Waveguides

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

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

Optically reconfigurable quasi-phase-matching in silicon nitride microresonators

Camille Sophie Brès, Jianqi Hu, Anton Stroganov, Edgars Nitiss

Quasi-phase-matching has long been a widely used approach in nonlinear photonics, enabling efficient parametric frequency conversions such as second-harmonic generation. However, in silicon photonics the task remains challenging, as materials best suited f ...

Nature Publishing Group2022