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Douaud, Alexandre

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Douaud

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Alexandre

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Université Laval. Département de chimie

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ncf13671723

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Résultats de recherche

Voici les éléments 1 - 6 sur 6
  • PublicationAccès libre
    Templated dewetting for self-assembled ultra low-loss chalcogenide integrated photonics
    (OSA Pub., 2021-10-11) Jean, Philippe; LaRochelle, Sophie; Shi, Wei; Messaddeq, Younès; Douaud, Alexandre
    Integrated photonics is of growing interest but relies on complex fabrication methods that have yet to match optical losses of bulkier platforms like optical fibers or whispering gallery mode resonators. Spontaneous matter reorganization phenomenon (e.g. dewetting) in thin-films provides a way for self-assembled structures with atomic scale surface rugosity, potentially alleviating the problems of roughness scattering loss and fabrication complexity. In this article, we study solid-state dewetting in chalcogenide glass thin-films and demonstrate its applicability to the fabrication of high-quality integrated photonics components. Optimal dewetting parameters are derived from a comprehensive experimental study of thin-film properties under high temperature rapid annealing. Atomic scale surface roughness are obtained using dewetting, with RMS values as low as Rq = 0.189 nm. Several integrated photonics components are fabricated using the method and characterized. We show that the use of pre-patterned templates leads to organized, reproducible patterns with large-scale uniformity and demonstrate the record high quality-factor of 4.7 × 106 in compact (R = 50 µm) microdisks, corresponding to 0.08 dB⋅cm−1 waveguide propagation loss. The integrated devices are directly fabricated on standard silicon-on-insulator dice using the micro-trench filling technique and coupled to silicon waveguides, making them readily deployable with existing silicon devices and systems.
  • PublicationAccès libre
    Sulfur-rich chalcogenide claddings for athermal and high-Q silicon microring resonators
    (OSA Pub., 2021-02-26) Jean, Philippe; LaRochelle, Sophie; Thibault, Tristan; Shi, Wei; Messaddeq, Younès; Douaud, Alexandre
    Heterogeneous integration of materials with a negative thermo-optic coefficient is a simple and efficient way to compensate the strong detrimental thermal dependence of silicon-on-insulator devices. Yet, the list of materials that are both amenable for photonics fabrication and exhibit a negative TOC is very short and often requires sacrificing loss performance. In this work, we demonstrate that As20S80 chalcogenide glass thin-films can be used to compensate silicon thermal effects in microring resonators while retaining excellent loss figures. We present an experimental characterization of the glass thin-film and of fabricated hybrid microring resonators at telecommunication wavelengths. Nearly athermal operation is demonstrated for the TM polarization with an absolute minimum measured resonance shift of 5.25 pm K−1, corresponding to a waveguide effective index thermal dependence of 4.28×10-6 RIU/K. We show that the thermal dependence can be controlled by changing the cladding thickness and a negative thermal dependence is obtained for the TM polarization. All configurations exhibit unprecedented low loss figures with a maximum measured intrinsic quality factor exceeding 3.9 × 105, corresponding to waveguide propagation loss of 1.37 dB cm−1. A value of−4.75(75)×10-5 RIU/K is measured for the thermo-optic coefficient of As20S80 thin-films.
  • PublicationRestreint
    Silicon-coupled tantalum pentoxide microresonators with broadband low thermo-optic coefficient
    (Optical Society, 2021-07-30) Jean, Philippe; Bah, Souleymane Toubou; LaRochelle, Sophie; Shi, Wei; Messaddeq, Younès; Douaud, Alexandre
    Stable microresonators are important integrated photonics components but are difficult to achieve on silicon-on-insulator due to silicon intrinsic properties. In this work, we demonstrate broadband thermally stable tantalum pentoxide microresonators directly coupled to silicon waveguides using a micro-trench co-integration method. The method combines in-foundry silicon processing with a single step backend thin-film deposition. The passive response of the microresonator and its thermal behavior are investigated. We show that the microresonator can operate in the overcoupled regime as well as near the critical coupling point, boasting an extinction ratio over 25 dB with no higher-order mode excitation. The temperature dependent wavelength shift is measured to be as low as 8.9 pm/K and remains below 10 pm/K over a 120 nm bandwidth.
  • PublicationAccès libre
    Silicon subwavelength grating waveguides with high-index chalcogenide glass cladding
    (Optical Society of America, 2021-06-17) Jean, Philippe; LaRochelle, Sophie; Shi, Wei; Messaddeq, Younès; Douaud, Alexandre
    Silicon subwavelength grating waveguides enable flexible design in integrated photonics through nano-scale refractive index engineering. Here, we explore the possibility of combining silicon subwavelength gratings waveguides with a high-index chalcogenide glass as a top cladding, thus modifying the waveguiding behavior and opening a new design axis for these structures. A detailed investigation of the heterogeneous SWG waveguide with high-index cladding is presented based on analytical and numerical simulations. We design, fabricate and characterize silicon subwavelength grating waveguide microring resonators with an As20S80 cladding. Thanks to As20S80 negative thermo-optic coefficient, we achieve near athermal behavior with a measured minimum thermally induced resonance shift of −1.54 pm/K, highlighting the potential of subwavelength grating waveguides for modal confinement engineering and to control light-matter interaction. We also show that the chalcogenide glass can be thermally reflowed to remove air gaps inside the cladding, resulting in a highly conformal structure. These types of waveguides can find application in reconfigurable photonics, nonlinear optics, metamaterials or slow light.
  • PublicationAccès libre
    Etchless chalcogenide microresonators monolithically coupled to silicon photonic waveguides
    (Optical Society of America, 2020-05-13) Messaddeq, Sandra Helena; Genest, Jérôme; Jean, Philippe; LaRochelle, Sophie; Shi, Wei; Messaddeq, Younès; Douaud, Alexandre; Michaud-Belleau, Vincent
    Integration of chalcogenide waveguides in silicon photonics can mitigate the prohibitive nonlinear losses ofsilicon while leveraging the mature CMOS-compatiblenanophotonic fabrication process. In this work, wedemonstrate, for the first time, a method of integratinghigh-Q chalcogenides microring resonators onto the sil-icon photonics platform without post-process etching.The method uses micro-trench filling and a novel ther-mal dewetting technique to form low-loss chalcogenidestrip waveguides. The microrings are integrated di-rectly inside silicon photonic circuits through evanes-cent coupling, providing an uncomplicated hybrid in-tegration scheme without the need to modify the exist-ing photonics foundry process. The microrings showa high quality factor exceeding 6⇥105near 1550 nmand propagation losses below 0.7 dB/cm, indicatinga promising solution for low-cost, compact nonlinearphotonic devices with applications in various fieldssuch as telecommunications and spectroscopy.
  • PublicationAccès libre
    Universal micro-trench resonators for monolithic integration with silicon waveguides
    (OSA Optical Materials Express, 2021-08-02) Jean, Philippe; Bah, Souleymane Toubou; LaRochelle, Sophie; Shi, Wei; Messaddeq, Younès; Douaud, Alexandre
    We present a systematic study of micro-trench resonators for heterogeneous integration with silicon waveguides. We experimentally and numerically demonstrate that the approach is compatible with a large variety of thin film materials and that it does not require specific etching recipe development, thus making it virtually universal. The microresonators are fabricated through in-foundry silicon-on-insulator processing and in-house backend processing. We also report ultra-compact chalcogenide microresonators with radius as small as 5µ and quality factors up to 1.8 × 105. We finally show a proof-of-concept of a novel multilayer waveguide using the micro-trench technique.