Christian Lafforgue

École Polytechnique Fédérale de Lausanne

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Laurent Vivien

Université Paris-Sud

Delphine Marris‐Morini

Centre de Nanosciences et de Nanotechnologies

ÉC

Éric Cassan

Université Paris-Saclay

Carlos Alonso‐Ramos

Centre de Nanosciences et de Nanotechnologies

Xavier Le Roux

Centre National de la Recherche Scientifique

Daniel Benedikovič

Centre de Nanosciences et de Nanotechnologies

Mathias Berciano

IMEC

Guillaume Marcaud

Université Paris-Saclay

Camille‐Sophie Brès

École Polytechnique Fédérale de Lausanne

Miguel Montesinos‐Ballester

ETH Zurich

Cooperative Institutions

Centre National de la Recherche Scientifique

136

Centre de Nanosciences et de Nanotechnologies

Université Paris-Saclay

Université Paris-Sud

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

Université Grenoble Alpes

CEA Grenoble

CEA LETI

École Polytechnique Fédérale de Lausanne

Institut National des Sciences Appliquées de Toulouse

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Silicon nitride integrated nonlinear photonics

Photoniques (2023)

Marco Clementi Christian Lafforgue Camille‐Sophie Brès

Silicon nitride (SiN) has emerged as a key platform for integrated nonlinear photonics by leveraging its excellent optical properties and high fabrication maturity. SiN nonlinear integrated devices can provide efficiency, bandwidth and practicality. Here we show their exceptional performances for Kerr comb generation and frequency conversion. We also show how by inducing the intrinsically lacking 2 nd order nonlinearity we can bring new nonlinear functionalities to the platform.

10.1051/photon/202312258

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Erbium-doped yttria-stabilised zirconia thin films grown by pulsed laser deposition for photonic applications

Thin Solid Films (2019)

Alicia Ruiz‐Caridad Guillaume Marcaud Joan Manel Ramírez Elena Durán‐Valdeiglesias Christian Lafforgue

Erbium

Pulsed Laser Deposition

10.1016/j.tsf.2019.137706

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Citations (3)

Mid-IR soliton microcomb generation in silicon nitride microring resonators

IET conference proceedings. (2023)

A. Karunakaran Marco Clementi Ozan Yakar Christian Lafforgue Anton Stroganov

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.

Free spectral range

10.1049/icp.2023.2365

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Heterogeneous silicon nitride waveguide integrated with few-layer WS₂ for on-chip nonlinear optics

Yuchen Wang Vincent Pelgrin Samuel Gyger Christian Lafforgue Val Zwiller

Recently, two-dimensional materials have attracted significant interests for nonlinear optics [1] . Here, we report on the experimental investigation and the numerical modelling of nonlinear pulse propagation in a heterogeneous silicon nitride channel waveguide with the integration of a few-layer WS 2 flake significantly increasing the effective nonlinearity.

Waveguide

Integrated Optics

10.1109/cleo/europe-eqec52157.2021.9542255

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Ultra-wideband flat anomalous dispersion in nanostructured silicon membrane waveguides (Conference Presentation)

Thi Thuy Duong Dinh Jianhao Zhang Miguel Montesinos‐Ballester Xavier Le Roux Christian Lafforgue

The Si transparency (1.1 μm – 8 μm wavelength) contains the strongest absorption features of a wide range of chemical and biological substances. However, the use of SOI in the mid-IR is hampered by the large absorption of the buried oxide (BOX) for wavelengths above 4 μm. Silicon membranes have garnered great interest for their unique capability to overcome the BOX limitation while leveraging the advantages of Si photonics. On the other hand, silicon is uniquely poised for the implementation of wideband mid-IR sources based on nonlinear frequency generation. Promising supercontinuum and frequency comb generation have already been demonstrated in Si. Still, current implementations have a limited flexibility in the engineering of phase-matching conditions and dispersion, which complicates the shaping of the nonlinear spectrum. Patterning Si with features smaller than half of the wavelength (well within the capabilities of standard large-volume fabrication processes) has proven to be a simple and powerful tool to implement metamaterials with optimally engineered properties. Here, we present the design of nanostructured silicon membrane waveguides with ultra-wideband flat anomalous dispersion in a wavelength span exceeding 5 µm. Our three-dimensional finite difference time domain (FDTD) calculations predict flat anomalous dispersion near 50 ps/km⋅nm between 2.5 µm and 8 µm wavelength. These results illustrate the potential of subwavelength metamaterial engineering to control chromatic dispersion in Si membrane waveguides. This is a promising step towards the implementation of wideband nonlinear sources in the mid-IR for silicon photonics.

Wideband

Supercontinuum

10.1117/12.2555819

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Subwavelength silicon nanostructuration for nonlinear and optomechanic applications

Thi Thuy Duong Dinh Jianhao Zhang Paula Nuño Ruano David González‐Andrade Xavier Le Roux

Periodically patterning silicon with a subwavelength pitch opens new degrees of freedom to control the propagation of light and sound in silicon photonic circuits with unprecedented flexibility. In this invited presentation, we will show our most recent results on the use suspended silicon waveguides for supercontinuum generation in the near-IR and mid-IR. We will also discuss our recent demonstrations of subwavelength engineering of photons and phonons in suspended and non-suspended silicon optomechanical cavities

Supercontinuum

10.1117/12.2650205

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Polarization and wavelength agnostic nanophotonic beam splitter

David González‐Andrade Christian Lafforgue Elena Durán‐Valdeiglesias Xavier Le Roux Mathias Berciano

High-performance optical beam splitters are of fundamental importance for the development of advanced silicon photonics integrated circuits. However, due to the high refractive index contrast of the silicon-on-insulator platform, state of the art Si splitters are hampered by trade-offs in bandwidth, polarization dependence and sensitivity to fabrication errors. Here, we present a new strategy that exploits modal engineering in slotted waveguides to overcome these limitations, enabling ultra-wideband polarization-insensitive optical power splitters, with relaxed fabrication tolerances. The proposed splitter relies on a single-mode slot waveguide which is transformed into two strip waveguides by a symmetric taper, yielding equal power splitting. Based on this concept, we experimentally demonstrate -3$\pm$0.5 dB polarization-independent transmission in an unprecedented 390 nm bandwidth (1260 - 1650 nm), even in the presence of waveguide width deviations as large as $\pm$25 nm.

Beam splitter

Splitter

Nanophotonics

Optical power

Waveguide

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Silicon photonics phase and intensity modulators for flat frequency comb generation

Photonics Research (2021)

Lucas Deniel Erwan Weckenmann Diego Pérez‐Galacho Christian Lafforgue S. Monfray

Flat electro-optical frequency combs play an important role in a wide range of applications, such as metrology, spectroscopy, or microwave photonics. As a key technology for the integration of optical circuits, silicon photonics could benefit from on-chip, tunable, flat frequency comb generators. In this article, two different architectures based on silicon modulators are studied for this purpose. They rely on a time to frequency conversion principle to shape the comb envelope. Using a numerical model of the silicon traveling-wave phase modulators, their driving schemes are optimized before their performances are simulated and compared. A total of nine lines could be obtained within a 2 dB flatness, with a line-spacing ranging from 0.1 to 7 GHz. Since this tunability is a major asset of electro-optical frequency combs, the effect of segmenting the phase modulators is finally investigated, showing that the flat lines spacing could be extended up to 39 GHz by this method.

Flatness (cosmology)

10.1364/prj.431282

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Citations (7)

Building blocks of silicon photonics

Semiconductors and semimetals (2019)

Laurent Vivien Charles Baudot F. Bœuf Bertrand Szelag Carlos Alonso‐Ramos

Silicon chip

10.1016/bs.semsem.2019.07.006

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Citations (5)

Novel Membrane Bioreactor with Gas/Liquid Two-Phase Flow for High-Performance Degradation of Phenol

Biotechnology Progress (1998)

David R. Leonard Muriel Mercier‐Bonin N.D. Lindley Christian Lafforgue

The use of a membrane bioreactor with cell retention to achieve high biomass concentrations has been examined for phenol degradation by the bacteria Alcaligenes eutrophus. This process is particularly interesting for toxic substrates as the hydraulic dilution rate and the growth rate are independently controlled. In the case of a transitory excess of phenol, this potentially toxic situation can be overcome by modifying the substrate concentration or the dilution rate without any loss of cells. The injection of a gas phase at the filter inlet increased both the permeate flow rate (by a factor of 1. 75) and the oxygen transfer capacity (by a factor of 1.5). This has enabled the cell concentration to reach a maximal value of 60 g L-1 with a hydraulic dilution rate of 0.5 h-1 and a phenol feed concentration of 8 g L-1. The volumetric productivity of this process corresponds to a phenol degradation rate approaching 100 kg m-3 day-1. The on-line measurement of the characteristic yellow color of 2-hydroxymuconate semialdehyde, a metabolic intermediate of the phenol degradation pathway, in the permeate provides an interesting basis for process control of phenol supply into the reactor since the color intensity correlates directly to the specific rate of phenol degradation.

Dilution

Degradation

Membrane bioreactor

10.1021/bp980069z

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Citations (19)