Cet article présente les principes de détection utilisant la spectroscopie infrarouge en photonique intégrée, en mettant en évidence les paramètres clés ainsi que leur ingénierie. Il décrit également les principales architectures de guides d’onde intégrés utilisées, et propose un état de l’art non exhaustif des molécules ayant été détectées démontrant la versatilité de cette technique.

Aluminum oxide offers an excellent platform for integrated photonics in the visible and ultraviolet ranges, combining low propagation losses, high index contrast with silica, and strong compatibility with rare earth dopants. This work reports a comprehensive study of 460 nm microring resonators in various configurations. The reported devices, obtained through a commercial multi-project wafer service, exhibit a record intrinsic quality factor of 3.6 × 105 on the aluminum oxide platform. Thermal tuning of the resonances is achieved via integrated metallic heaters, with a tuning efficiency of 1.63 pm/mW over a 500 pm range. These results demonstrate fully integrated photonic functionalities in the visible range, opening new prospects for sensing, spectroscopy, and quantum photonic applications.

Radiofrequency (RF) magnetron sputtering is used to deposit 5000 ppmw Dy3+-doped selenide thin films on SiO2 or undoped sulfide confinement layers on silicon substrates. Then, photolithography and dry etching techniques are implemented to fabricate rare-earth-doped selenide ridge waveguides. The investigation was focused on the influence of argon deposition pressure on amorphous chalcogenide thin films' properties with special attention to luminescence. Fluorescence in short-wave and midwave infrared spectral ranges is recorded using optical excitation at 1.32 mu m. The argon pressure of 1 x 10-2 mbar gives the highest and clearest signal in the midwave infrared region. At 4.38 mu m, single-mode optical propagation is efficiently observed in 5000 ppmw Dy3+-doped Ga5Ge20Sb10Se65 waveguides deposited on an undoped sulfide confinement layer on the silicon substrate.

RF magnetron cosputtered amorphous Ge-Bi-Se films were fabricated using polycrystalline GeSe2 and Bi2Se3 targets. Their structural, linear, and nonlinear optical properties were studied to understand compositional influence for future photonic applications. A broader Ge-Bi-Se amorphous region with a noticeably high bismuth atomic percentage (up to at % Bi = 36%) is observed using this deposition method compared to <= 16 at % in the conventional Ge20Se80-x Bi x bulk glass synthesis []. The structural characteristics of the cosputtered films were analyzed using Raman spectroscopy, where increasing bismuth concentration shifted all vibrational bands to the lower energy side with reduced intensity. A decrease in optical band gap energy values from 2.04 (+/- 0.02) eV (Bi atom % = 0) to 0.73 (+/- 0.02) eV (Bi atom % = 36) and the corresponding increase in refractive index value n from 2.41 (+/- 0.01) to 4.09 (+/- 0.01) at telecommunication wavelength indicate the strong influence of bismuth on the optical properties of the films. Third-order nonlinear optical parameters were calculated from linear parameters using semiempirical equations and Sheik-Bahae formalism in order to allow their prediction according to the film composition and taking into account the wavelength of use. Following these simulations, which enabled the selection of promising compositions in terms of optical nonlinearity applications, this work also focused on demonstrating the feasibility of manufacturing ridge waveguides from these cosputtered films by RF magnetron using dry etching with the aim of offering Ge-Bi-Se-based integrated optical circuits.

This study presents the etching parameters optimization of GeSbSe-based chalcogenide glass (ChG) for near and mid-infrared integrated photonic applications. Single-mode Se4 (Ge19.4Sb16.7Se63.9) on Se2 (Ge28.1Sb6.3Se65.6) waveguides were designed and fabricated. The Se2 and Se4 layers were first deposited via the RF magnetron sputtering technique. The waveguide structures were then patterned using combined reactive ion -inductively coupled plasma (RIE-ICP) etching and optimized by introducing argon gas to the fluorine (CHF3)-based chemistry etching. Parametric investigation of etching conditions, particularly the Ar/(CHF3 + Ar) ratio and total gas flow rates, led to significant improvements in waveguide sidewall morphology and roughness. Consequently, propagation losses were reduced from 7.5 dB/cm to 2.6 dB/cm, at near-infrared wavelengths (lambda=1,55 mu m). In the mid-infrared region, the optimized process achieved a low propagation loss of (1.45 +/- 0.81) dB/cm at 4.11 mu m, with an average loss of approximately 4 dB/cm across the 4.1-4.55 mu m wavelength range. This marks a substantial improvement over the initial process, which exhibited an average loss of 15 dB/cm. Advanced characterization techniques, including SEM-based roughness extraction and optical scattering loss modeling, were employed to correlate surface morphology with etching parameters. The Payne-Lacey model was used to predict propagation losses, showing good agreement with experimental results. This comprehensive approach provides valuable insights into the relationship between etching conditions and waveguide performance, contributing significantly to the development of low-loss chalcogenide-based photonic devices for near- and mid-infrared applications.

Mid-infrared (mid-IR) waveguide sensors were fabricated using two platforms: chalcogenide glasses (ChGs) and porous silicon (PSi). ChGs layers were deposited through RF magnetron sputtering while PSi layers were prepared by electrochemical anodization. Ridge waveguides were patterned using standard i-line photolithography and reactive ion etching for both platforms. The ChGs waveguides exhibit a wide transparency range from λ = 3.94 to 8.95 µm, with a minimum propagation losses value of 2.5 dB/cm at λ = 7.58 µm, while PSi transparency range is from λ = 3.94 to 4.55 µm with a minimum propagation losses value of 9.1 dB/cm at λ = 4.12 µm. To validate the proposed ChGs sensor, a spectroscopic liquid sensing experiment was performed using acetonitrile and isopropanol. The results showed an estimated limit of detection (LoD) of 610 ppm at λ = 4.44 µm for acetonitrile and a LoD of 300 ppm at λ = 7.25 µm for isopropanol, enabled by the evanescent field interaction. Regarding gas sensing, CO2 was used as the analyte. A LoD of 17000 ppm at λ = 4.28 µm was achieved using the ChGs platform. The sensing application was improved with the PSi platform. Due to the open pores, light and gas molecules interact within the internal volume, unlike the ChGs platform, where the interaction occurs with the evanescent part of the light. This results in an exalted external confinement factor, Γ, over 75 times greater for the PSi platform, achieving a LoD of 600 ppm at λ = 4.26 µm for CO2 sensing. Estimation of concentrations from mixtures of two solutions through deconvolution of the measured spectra was also achieved with good approximations, validating the transduction capabilities in a complex environment using the ChGs platform.

The development of Al2O3-based integrated components in the blue/near-UV range is reported. An MMI splitting ratio of 3.20±0.34 dB/port at 405 nm and microring resonators quality factors of 2.1*105 measured at 460 nm are demonstrated.

Research on integrated blue and near-ultraviolet photonics has been increasingly investigated in recent years. To enable the development of photonic integrated circuits in this wavelength range, one of the challenges is to identify a transparent platform that can provide a variety of integrated components. Aluminum oxide (Al2O3) was demonstrated to exhibit low propagation losses for wavelengths below 450 nm, making it a very promising platform to operate at short wavelengths. MMIs are very convenient integrated components for splitting or combining signals and can be used for many applications such as on-chip spectrometry or microscopy. The development of a 50/50 coupler at 405 nm is reported based on symmetrical multimode interferometer (MMI) presenting a splitting ratio of 3.20 +/- 0.34 dB/MMI. Characterizations at 375, 420, and 454 nm are also presented.

A mid-infrared (mid-IR) porous silicon (PSi) waveguide gas sensor was fabricated.PSi guiding and confinement layers were prepared by electrochemical anodization.Ridge waveguides were patterned using standard i-line photolithography and reactive ion etching.Due to the open pores, light and gas molecules interact in the inside volume, unlike bulk material in which the interaction takes place with the evanescent part of the light.Propagation losses are measured for a wavelength range spanning from λ = 3.9 to 4.55 µm with a value of 11.4 dB/cm at λ = 4.28 µm.The influence of native oxidation and ageing on the propagation losses was investigated.Limit of detection (LoD) of 1000 ppm is obtained with the waveguide sensor at the carbon dioxide (CO 2 ) absorption peak at λ = 4.28 µm.

In this paper, we report on the infrared luminescence of amorphous praseodymium-doped Ge20In5Sb10Se65 waveguides, which can be used as infrared sources in photonic integrated circuits on silicon substrates. Amorphous chalcogenide thin films were deposited by radiofrequency magnetron cosputtering using an argon plasma whose deposition parameters were optimized for chalcogenide materials. The micropatterning as ridge waveguides of the chalcogenide cosputtered films was performed using photolithography and plasma-coupled reactive ion etching techniques. The influence of the rare earth concentration within those thin films on their optical properties and rare earth spectroscopic properties was investigated. Using an excitation wavelength of 1.55 μm, the mid-infrared luminescence of Pr3+ ions from 2.5 to 5.5 μm was clearly demonstrated for studied chalcogenide materials. A wide range of waveguide widths and doping ratios were tested, assessing the ability of the cosputtering technique to preserve the luminescence properties of the rare earth ions initially observed in the bulk glass through the thin-film deposition and patterning process.

Rapid, simultaneous detection of organic chemical pollutants in water is an important issue to solve for protecting human health. This study investigated the possibility of developing an in situ reusable optical sensor capable of selective measurements utilizing a chalcogenide transducer supplemented by a hydrophobic polymer membrane with detection based on evanescent waves in the mid-infrared spectrum. In order to optimise a polyisobutylene hydrophobic film deposited on a chalcogenide waveguide, a zinc selenide prism was utilized as a testbed for performing attenuated total reflection with Fourier-transform infrared spectroscopy. To comply with the levels mentioned in health guidelines, the target detection range in this study was kept rather low, with the concentration range extended from 50 ppb to 100 ppm to cover accidental pollution problems, while targeted hydrocarbons (benzene, toluene, and xylene) were still detected at a concentration of 100 ppb. Infrared measurements in the selected range showed a linear behaviour, with the exception of two constantly reproducible plateau phases around 25 and 80 ppm, which were observable for two polymer film thicknesses of 5 and 10 mu m. The polymer was also found to be reusable by regenerating it with water between individual measurements by increasing the water temperature and flow to facilitate reverse exchange kinetics. Given the good conformability of the hydrophobic polymer when coated on chalcogenide photonic circuits and its demonstrated ability to detect organic pollutants in water and to be regenerated afterwards, a microfluidic channel utilising water flow over an evanescent wave optical transducer based on a chalcogenide waveguide and a polyisobutylene (PIB) hydrophobic layer deposited on its surface was successfully fabricated from polydimethylsiloxane by filling a mold prepared via CAD and 3D printing techniques. Optimisation of the functionalisation of infrared chalcogenide sensors for accidental water pollution using a hydrophobic polymer.

Chalcogenide glasses have attracted attention for sensing applications due to their high transparency in the infrared range, their ability to be fabricated into thin films by PVD and to be processed into integrated photonic components by photolithography and etching. We will present the development of a chalcogenide-based mid-infrared platform dedicated to mid-infrared spectroscopy using evanescent waves. This study represents an important step towards the development of an optical sensor in the MIR spectral range using chalcogenide materials for the detection of organic molecules in water.

Climate-active gases, notably carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), display fundamental absorption bands in the mid-infrared (mid-IR). The detection and monitoring of those gases could be enabled by the development of mid-IR optical sources. Broadband mid-IR on-chip light emission from rare-earth-doped chalcogenide photonic integrated circuits could provide a compact, efficient, and cost-effective gas sensing solution. Mid-IR photoluminescence of dysprosium-doped selenide ridge waveguides obtained under optical pumping at a telecommunication wavelength (∼1.3 µm) is investigated for Dy3+ ion concentrations in the 2500-10,000 ppmw range. CO2 detection at around 4.3 µm is then demonstrated based on absorption of this broadband mid-IR emission.

In this paper, the design of integrated photonics components for blue/near-ultraviolet wavelength range is presented. Optical properties of the silicon oxynitride (SiON) in this spectral range are exploited to develop a complete library of photonic integrated components for operation in blue/near-UV spectral range