arXiv subjects

Maximilien Billet

Publications and source records attributed to Maximilien Billet.

14 recordsLinked to original sources

arXiv2026

Micro-transfer Printed Blue InGaN Lasers on Silicon Nitride Photonic Integrated Circuits

Expanding integrated photonics into the blue spectral range requires high-performance light sources, making the gallium nitride (GaN) material family indispensable. While silicon nitride (SiN) platforms offer a robust, CMOS compatible passive ecosystem for visible wavelengths, seamlessly integrating GaN lasers remains a major bottleneck. Conventional heterogeneous integration methods present distinct trade-offs: full-wafer bonding achieves high throughput but requires careful management of thermal and lattice mismatches across large areas, whereas flip-chip bonding ensures high yield through pretesting but is constrained by sequential processing speed. In this landscape, micro-transfer printing (MTP) emerges as a disruptive, material-efficient alternative, bypassing these limitations by combining high-density parallel integration with known-good-die selection. Applying MTP to GaN, however, presents a significant material challenge: due to its chemical inertness and strong III-N bonds, device release typically relies on electrochemical etching, which can compromise material quality. Here, we overcome this hurdle and demonstrate the first micro-transfer printed blue lasers on a SiN platform. Using a heavily doped n-type sacrificial layer together with optimized electrochemical etching conditions, we release smooth-surfaced thin-film light sources from bulk GaN substrates. Following release, the devices are integrated and butt-coupled to SiN fork-shaped edge couplers, achieving high current densities exceeding 20 kA$/$cm$^2$ alongside lasing at 455 nm. These results expand the visible integrated photonic toolkit and establish a framework for multi-wavelength integration, opening new avenues for next-generation technologies including flow cytometry, quantum computing, optical communications, and augmented/virtual reality.

physics.optics↗

arXiv2026

A Heterogeneous 200 mm Silicon Nitride Photonics Platform for Visible-to-Near-Infrared Applications via Micro-Transfer Printing

The commercialization of next-generation technologies, including optical interconnects, quantum computing, AR/VR, and medical diagnostics, requires a low-loss photonic platform offering compact, multifunctional systems in the visible and near-infrared range. Although silicon nitride (SiN) is an excellent material due to its ultra-low loss and broad transparency window, integrating active components such as light sources, modulators and photodetectors from diverse material platforms in a scalable, reliable way remains challenging. Micro-transfer printing is an emerging wafer-scale heterogeneous integration technology that can be implemented as a back-end post-processing step without disrupting the primary in-line fabrication process. In this work, we present a dual LPCVD SiN layer platform fabricated in a 200 mm CMOS pilot line, that incorporates micro-transfer printing modules, allowing the integration of active components on well defined recesses. A hydrogenated amorphous silicon layer is also available to increase the versatility of the platform allowing for evanescently-coupled III-V lasers as well as other passive functionality in the near-infrared region. We report full wafer-scale measurements showing low optical SiN losses of 4 dB/cm and 0.23 dB/cm at a wavelength of 488 nm and 940 nm respectively. In addition, a transition loss of only 0.35 dB is obtained from the SiN to the a-Si:H layer, in good agreement with simulated values. Finally, to showcase more advanced functionality, GaAs-based gain sections are micro-transfer printed on several dies, achieving consistent die-to-die lasing at 970 nm with on-chip optical powers of approximately 1 mW. These results showcase the potential of the integrated photonics platform towards unlocking a wide range of new applications in the sub-1-$μ$m spectral region.

physics.optics↗

arXiv2026

Micro-Transfer Printing of Lithium Niobate on 200 mm Silicon Photonics: A High-Speed Heterogeneous Wafer-Scale Platform

The rapid growth of artificial intelligence (AI) and other data center applications is driving the demand for photonic interconnects that combine high-speed with low energy consumption, making scalability a critical requirement. Micro-transfer printing (MTP) has emerged as a promising technique for the wafer-scale heterogeneous integration of thin film lithium niobate (TFLN) onto silicon photonics (SiPho) platforms. Here, we demonstrate heterogeneous SiPho TFLN integration across four full 200 mm wafers with a 3sigma placement accuracy down to 420 nm and a printing yield of larger than 95percentage. Low insertion loss less than 2 dB over 600 phase modulators (300 amplitude modulators) is achieved. A half wave voltage of 4 V in push pull configuration, and high-speed modulation with a bandwith larger than 70 GHz is demonstrated on a subset of tested devices.

physics.optics↗

arXiv2026

A variability-aware simulation and design workflow for wafer-scale, heterogeneously integrated lithium niobate modulators

We present a variability-aware simulation framework for heterogeneously integrated lithium niobate traveling-wave modulators. The framework incorporates fabrication-variation data obtained from our dedicated pilot line and enables efficient optimisation of geometric parameters to ensure stable device performance across wafer-scale manufacturing. The proposed multi-parameter optimisation method enables the efficient identification of modulator designs that simultaneously achieve target performance metrics (Vpi, optical insertion loss, and 3dB electro-optic bandwidth) while maintaining robustness against fabrication-induced variations. Using this methodology on two representative modulator architectures, we theoretically demonstrate that reliable wafer-scale integration of lithium niobate modulators on silicon photonics via micro-transfer printing is feasible and can be systematically engineered.

physics.optics↗

arXiv2026

Thin-film lithium tantalate for ultraviolet integrated electro-optic modulator

The realization of integrated, high-speed ultraviolet (UV) modulation is pivotal for the advancement of quantum information processing, portable atomic clocks, and secure solar-blind communications. While mature photonic platforms have facilitated sophisticated system-level integration across visible and infrared spectra, high-speed active modulation in UV remains with traditional bulk crystals. Consequently, a scalable integrated solution that simultaneously combines low insertion loss and extreme compactness with high modulation efficiency has remained challenging. Here, we report the first integrated UV electro-optic modulator on a thin-film lithium tantalate (TFLT) platform. By employing a compact lumped-electrode design, we achieve a record-low VπL of 85 mV\cdot cm at 375 nm, providing an up to four orders of magnitude improvement in terms of bandwidth/Vπ L over bulk technologies. The device demonstrates a robust extinction ratio of 22.7 dB, a low insertion loss of 1.3 dB, and a Vπ of 4.2V. Although the measured 3-dB bandwidth of 922 MHz is currently limited by photodetector performance, the small device footprint of 1.16 mm and electrode design of 200 μm indicate intrinsic potential for high-speed operation beyond 67 GHz which is confirmed by the electrical-to-electrical response. This work establishes TFLT as a disruptive platform for wafer-scale compatible active UV photonics, enabling the next generation of scalable quantum and communication systems.

physics.optics↗

arXiv2025

Micro-Transfer Printed Continuous-Wave and Mode-Locked Laser Integration at 800 nm on a Silicon Nitride Platform

Applications such as augmented and virtual reality (AR/VR), optical atomic clocks, and quantum computing require photonic integration of (near-)visible laser sources to enable commercialization at scale. The heterogeneous integration of III-V optical gain materials with low-loss silicon nitride waveguides enables complex photonic circuits with low-noise lasers on a single chip. Previous such demonstrations are mostly geared towards telecommunication wavelengths. At shorter wavelengths, limited options exist for efficient light coupling between III-V and silicon nitride waveguides. Recent advances in wafer-bonded devices at these wavelengths require complex coupling structures and suffer from poor heat dissipation. Here, we overcome these challenges and demonstrate a wafer-scale micro-transfer printing method integrating functional III-V devices directly onto the silicon substrate of a commercial silicon nitride platform. We show butt-coupling of efficient GaAs-based amplifiers operating at 800 nm with integrated saturable absorbers to silicon nitride cavities. This resulted in extended-cavity continuous-wave and mode-locked lasers generating pulse trains with repetition rates ranging from 3.2 to 9.2 GHz and excellent passive stability with a fundamental radio-frequency linewidth of 519 Hz. These results show the potential to build complex, high-performance fully-integrated laser systems at 800 nm using scalable manufacturing, promising advances for AR/VR, nonlinear photonics, timekeeping, quantum computing, and beyond.

physics.optics↗

arXiv2025

A high-speed heterogeneous lithium tantalate silicon photonics platform

The rapid expansion of cloud computing and artificial intelligence has driven the demand for faster optical components in data centres to unprecedented levels. A key advancement in this field is the integration of multiple photonic components onto a single chip, enhancing the performance of optical transceivers. Here, silicon photonics, benefiting from mature fabrication processes, has gained prominence. The platform combines modulators, switches, photodetectors and low-loss waveguides on a single chip. However, emerging standards like 1600ZR+ potentially exceed the capabilities of silicon-based modulators. To address these limitations, thin-film lithium niobate has been proposed as an alternative to silicon photonics, offering a low voltage-length product and exceptional high-speed modulation properties. More recently, the first demonstrations of thin-film lithium tantalate circuits have emerged, addressing some of the disadvantages of lithium niobate enabling a reduced bias drift and enhanced resistance to optical damage. As such, making it a promising candidate for next-generation photonic platforms. However, a persistent drawback of such platforms is the lithium contamination, which complicates integration with CMOS fabrication processes. Here, we present for the first time the integration of lithium tantalate onto a silicon photonics chip. This integration is achieved without modifying the standard silicon photonics process design kit. Our device achieves low half-wave voltage (3.5 V), low insertion loss (2.9 dB) and high-speed operation (> 70 GHz), paving the way for next-gen applications. By minimising lithium tantalate material use, our approach reduces costs while leveraging existing silicon photonics technology advancements, in particular supporting ultra-fast monolithic germanium photodetectors and established process design kits.

physics.optics↗

arXiv2025

Centimetre-Scale Micro-Transfer Printing to enable Heterogeneous Integration of Thin Film Lithium Niobate with Silicon Photonics

The integrated photonics CMOS-compatible silicon nitride (SiN) platform is praised for its low propagation loss, but is limited by its lack of active functionalities such as a strong Pockels coefficient and intrinsic \c{hi}(2) nonlinearity. In this paper, we demonstrate the integration of centimetre-long thin-film lithium niobate (TFLN) devices on a SiN platform using the micro-transfer printing (uTP) method. At a wavelength of 1550 nm, propagation losses of approximately 0.9 dB/cm and transition losses of 1.8 dB per facet were measured. Furthermore, the TFLN was integrated into an imbalanced push-pull Mach-Zehnder modulator, achieving a Vπ of 3.2 V. The electro-optics nature of the observed modulation is confirmed by measuring the device up to 35 GHz, showing that the printing does not affect the high-speed LN properties.

physics.optics↗

arXiv2024

Integrated resonant electro-optic comb enabled by platform-agnostic laser integration

The field of integrated photonics has significantly impacted numerous fields including communication, sensing, and quantum physics owing to the efficiency, speed, and compactness of its devices. However, the reliance on off-chip bulk lasers compromises the compact nature of these systems. While silicon photonics and III-V platforms have established integrated laser technologies, emerging demands for ultra-low optical loss, wider bandgaps, and optical nonlinearities necessitate other platforms. Developing integrated lasers on less mature platforms is arduous and costly due to limited throughput or unconventional process requirements. In response, we propose a novel platform-agnostic laser integration technique utilizing a singular design and process flow, applicable without modification to a diverse range of platforms. Leveraging a two-step micro-transfer printing method, we achieve nearly identical laser performance across platforms with refractive indices between 1.7 and 2.5. Experimental validation demonstrates strikingly similar laser characteristics between devices processed on lithium niobate and silicon nitride platforms. Furthermore, we showcase the integration of a laser with a resonant electro-optic comb generator on the thin-film lithium niobate platform, producing over 80 comb lines spanning 12 nm. This versatile technique transcends platform-specific limitations, facilitating applications like microwave photonics, handheld spectrometers, and cost-effective Lidar systems, across multiple platforms.

physics.optics↗

arXiv2023

Micro-transfer-printed Thin film lithium niobate (TFLN)-on-Silicon Ring Modulator

Thin-film lithium niobate (TFLN) has a proven record of building high-performance electro-optical (EO) modulators. However, its CMOS incompatibility and the need for non-standard etching have consistently posed challenges in terms of scalability, standardization, and the complexity of integration. Heterogeneous integration comes to solve this key challenge. Micro-transfer printing of thin-film lithium niobate brings TFLN to well-established silicon ecosystem by easy "pick and place", which showcases immense potential in constructing high-density, cost-effective, highly versatile heterogeneous integrated circuits. Here, we demonstrated for the first time a micro-transfer-printed thin film lithium niobate (TFLN)-on-silicon ring modulator, which is an important step towards dense integration of performant lithium niobate modulators with compact and scalable silicon circuity. The presented device exhibits an insertion loss of -1.5dB, extinction ratio of -37dB, electro-optical bandwidth of 16GHz and modulation rates up to 45Gps.

physics.optics↗

arXiv2023

Reliable micro-transfer printing method for heterogeneous integration of lithium niobate and semiconductor thin films

High-speed Pockels modulation and second-order nonlinearities are key components in optical systems, but CMOS-compatible platforms like silicon and silicon nitride lack these capabilities. Micro-transfer printing of thin-film lithium niobate offers a solution, but suspending large areas of thin films for long interaction lengths and high-Q resonators is challenging, resulting in a low transfer yield. We present a new source preparation method that enables reliable transfer printing of thin-film lithium niobate. We demonstrate its versatility by successfully applying it to gallium phosphide and silicon, and provide an estimate of the transfer yield by subsequently printing 25 lithium niobate films without fail.

physics.optics↗

arXiv2020

Supercontinuum generation assisted by dispersive waves trapping in dispersion-managed integrated silicon waveguides

Compact chip-scale comb sources are of significant interest for many practical applications. Here, we experimentally study the generation of supercontinuum (SC) in an axially varying integrated waveguide. We show that the local tuning of the dispersion enables the continuous blue shift of dispersive waves thanks to their trapping by the strongly compressed pump pulse. This mechanism provides new insight into supercontinuum generation in a dispersion varying integrated waveguide. Pumped close to 2.2 $μ$m in the femtosecond regime and at a pulse energy of $\sim$ 4 pJ, the output spectrum extends from 1.1 $μ$m up to 2.76 $μ$m and shows good coherence properties. Octave-spanning SC is also observed at input energy as low as $\sim$ 0.9 pJ. We show that the supercontinuum is more robust against variations of the input pulse parameters and is also spectrally flatter in our numerically optimized waveguide than in fixed-width waveguides. This research demonstrates the potential of dispersion varying waveguides for coherent SC generation and paves the way for integrated low power applications, such as chip-scale frequency comb generation, precision spectroscopy, optical frequency metrology, and wide-band wavelength division multiplexing in the near-infrared.

physics.optics↗

arXiv2020

Second Harmonic Generation Enabled by Longitudinal Electric Field Components in Photonic Wire Waveguides

We investigate type I second harmonic generation in III-V semiconductor wire waveguides aligned with a crystallographic axis. In this direction, because of the single nonzero tensor element of III-V semiconductors, only frequency conversion by mixing with the longitudinal components of the optical fields is allowed. We experimentally study the impact of the propagation direction on the conversion efficiency and confirm the role played by the longitudinal components through the excitation of an antisymmetric second harmonic higher order mode.

physics.optics↗

arXiv2020

Full Vectorial Modeling of Second Harmonic Generation in III-V-on-insulator Nanowires

We model second harmonic generation in subwavelength III-V-on-insulator waveguides. The large index contrast induces strong longitudinal electric field components that play an important role in the nonlinear conversion. We show that many different waveguide dimensions are suitable for efficient conversion of a fundamental quasi-TE pump mode around the 1550 nm telecommunication wavelength to a higher-order second harmonic mode.

physics.optics↗