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We report the fabrication and the physical and optical characterizations of sulphide GaxGe25-xSb10S65(x=0,5) rib waveguides. High quality films fabricated on SiO2/Si wafer substrates were obtained using the sputtering magnetron rf deposition method. The slab waveguides obtained without annealing present propagation losses of about 0.6 dB/cm at 1550 nm. These optical losses are not important for implementation in optical devices based on silicon-on-insulator or polymer, for instance, atomic force microscopy measurements revealed low interface roughness between the different media (substrate/film and film/air). Reactive ion etching was used to pattern rib waveguides between 2 and 300 μm wide. The parameters were optimized to obtain a dry etching process that had low surface roughness, vertical sidewalls, etch depth of more than 1 μm, and reasonable etching rate. This technique was used to fabricate Y optical junctions for optical interconnections on chalcogenide amorphous films. Their optical transmission was demonstrated by optical near field of guided modes and optical losses were measured and discussed. [ABSTRACT FROM AUTHOR]

In this paper, we report on the design and the overall realization of micro-resonators based on the development of adequate processes on a UV210 polymer. These micro-optical structures are developed by deep ultraviolet lithography allowing fabrication of nano-structured devices by means of low cost and reproducible processes. Two families of resonant micro-structures shaped on disk and stadium with various sizes are investigated. Structural and optical imaging characterizations have been carried out to ensure their ability to act as resonant integrated micro-structures. At first, scanning electron microscopy and Nomarsky microscopy studies confirm the UV-light process resolution down to 450 nm developed on a UV210 polymer. Then, optical characterizations have been performed as regards intensity and spectral properties of such micro-resonators. Field intensity measurements in visible and infrared ranges have been realized and validate light propagation by evanescent coupling between waveguides and micro-resonators. Finally, spectral analyses on TE modes demonstrate the presence of optical resonances with 1.45 nm and 2.19 nm free spectral range values for respectively disk and stadium micro-structures. The UV210 polymer appears appropriate for the realization of micro-structures requiring a few hundred nanometers gap-scale while maintaining adequate spectral properties for versatile applications in telecommunication and metrology [ABSTRACT FROM AUTHOR]

This paper reports the fabrication of luminescent optical rib/ridge waveguides made of erbium doped Ga-Ge-Sb-S films deposited by RF magnetron sputtering. Several fluorescence emissions of Er 3+ ions from the visible to the middle infrared spectral domain were clearly observed within the films. The study of the 4 I 13/2 level lifetime enabled development of a suitable annealing treatment of the films to reach the value of the bulk counterpart while the variation in surface roughness was limited, thus ensuring reasonable optical losses (0.7–0.9 dB/cm). Amplification experiments were carried out at 1.54 μm leading to complete characterization of the erbium-doped micro-waveguide with ∼3.4 dB/cm on/off gain. A demonstration of mid-IR photoluminescence from Er 3+ -doped chalcogenide micro-waveguide was recorded at ∼2.76 μm. The multi-luminescence from the visible to mid-IR generated using erbium doped chalcogenide waveguiding micro-structures might find easy-to-use applications concerning telecommunication technologies or on-chip optical sensors for which luminescent sources or amplifiers operating at different wavelengths are required. [ABSTRACT FROM AUTHOR]

Abstract: Amorphous chalcogenide films play a motivating role in the development of integrated planar optical circuits due to their potential functionality in near infrared (IR) and mid-IR spectral regions. More specifically, the photoluminescence of rare earth ions in amorphous chalcogenide films can be used in laser and amplifier devices in the IR spectral domain. The aim of the present investigation was to optimize the deposition conditions for the fabrication of undoped and Er3+ doped sulphide and selenide thin films with nominal composition Ga5Ge20Sb10S(Se)65 or Ga5Ge23Sb5S67 by pulsed laser deposition (PLD). The study of compositional, morphological and structural characteristics of the layers was realized by scanning electron microscopy–energy dispersive spectroscopy, atomic force microscopy and Raman spectroscopy analyses, respectively. Some optical properties (transmittance, index of refraction, optical band gap, etc.) of prepared chalcogenide films and optical losses were investigated as well. The clear identification of near-IR photoluminescence of Er3+ ions was obtained for both selenide and sulphide films. The decay of the 4I13/2 → 4I15/2 transition at 1.54µm in Er3+ doped Ga5Ge20Sb10S65 PLD sulphide films was studied to assess the effects of film thickness, rare earth concentration and multilayer PLD deposition on their spectroscopic properties. [Copyright &y& Elsevier]

Abstract: Integration of microcrystalline silicon Thin Film Transistors (TFTs) and excimer laser crystallized silicon TFTs on the same substrate is performed with the objective to limit the maximum temperature of the process to 200 °C. For the second type of TFTs, the laser crystallization of 200 nm thick microcrystalline silicon deposited film was optimised first. The maximum electron mobility of both μc-Si and laser crystallized TFTs is 4 cm2/V s and 400 cm2/V s respectively. [Copyright &y& Elsevier]

Abstract: N-type as well P-type top-gate microcrystalline silicon thin film transistors (TFTs) are fabricated on glass substrates at a maximum temperature of 200 °C. The active layer is an undoped μc-Si film, 200 nm thick, deposited by Hot-Wire Chemical Vapor. The drain and source regions are highly phosphorus (N-type TFTs) or boron (P-type TFTs)-doped μc-films deposited by HW-CVD. The gate insulator is a silicon dioxide film deposited by RF sputtering. Al–SiO2–N type c-Si structures using this insulator present low flat-band voltage,−0.2 V, and low density of states at the interface D it=6.4×1010 eV−1 cm−2. High field effect mobility, 25 cm2/V s for electrons and 1.1 cm2/V s for holes, is obtained. These values are very high, particularly the hole mobility that was never reached previously. [Copyright &y& Elsevier]

This paper describes the thin-film fabrication process and the performance of 60-GHz aperture-coupled microstrip patch antennas printed on fused quartz substrates. It is shown that their characteristics (input impedance, axial ratio) are strongly modified by residual air gaps located between the two substrates of the antenna. In particular, FDTD simulations demonstrate that these parasitic effects can be minimized by using two ground/reflecting planes and by keeping the thickness of the air layer thinner than λ0/250, where λ0 is the free-space wavelength. To face this technological problem, two intermediate metal and adhesive (low-temperature) wafer bonding techniques, respectively based on indium and polymer layers, have been developed and validated experimentally for linear and circular polarization patch antennas and arrays. The lift-off fabrication process is also described. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 41–47, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11281 [ABSTRACT FROM AUTHOR]

The development and the ability of an optical integrated polymeric resonator, acting as a surface light probe, for monitoring temperature-induced supramolecular phase transitions is presented in this work. The homogeneous detection of the transitions between different self-assembled structures in an aqueous solution of fatty acids (12-hydroxystearic acid, in association with amino-pentanol) was studied by investigating the coupling between the solution and the integrated photonic micro-cavity. Tuning the self-organized assemblies of surfactant is very attractive for many applications, such as cosmetic products, food, drug delivery and medical, and the development of alternative tools – especially those requiring minute amount of solution – to monitor their structural changes are essential. These original studies at temperatures ranging from 17 to 24 °C, based on a statistical treatment of optical resonance spectra, have evidenced the thermoresponsive nature of the optical features, and that different regimes occur with temperature. The optical results were corroborated with the measurement of the solution viscosity as a function of temperature, confirming that we can ascribe the optically-detected regimes to a surfactant assembly shifting reversibly from a tubular shape to a micellar one. The comparison between the optical and the rheological responses showed different accuracies: while the viscosity data exhibited a rather smooth and monotonous transition, the behavior changes were sharper and non-monotonous in terms of optical properties, allowing us to unambiguously identify in intermediate regime between 18.5 and 20 °C. These morphological transition experiments represent a unique opportunity to extend the numbers of available techniques studying these systems through integrated optical techniques with potential opportunities of real time detection and working on low sampling volume. • Dynamic evolution of the fatty acid phase transition and morphological transition assessed by resonant probe light. • Monitoring of temperature-induced supramolecular phase transitions between various self-assembled structures. • Optically-detected transition to a surfactant assembly shifting: reversibly from a tubular shape to a micellar one. • Measurements of the solution viscosity as a function of temperature. [ABSTRACT FROM AUTHOR]