Nanostructuring lithium niobate substrates by focused ion beam milling

We report on two novel ways for patterning Lithium Niobate (LN) at submicronic scale by means of focused ion beam (FIB) bombardment. The first method consists of direct FIB milling on LiNbO3 and the second one is a combination of FIB milling on a deposited metallic layer and subsequent RIE (Reactive Ion Etching) etching. FIB images show in both cases homogeneous structures with well reproduced periodicity. These methods open the way to the fabrication of photonic crystals on LiNbO3 substrates

Experimental and numerical analysis of the chromatic dispersion dependence upon the actual profile of small core microstructured fibres

International audienceThe chromatic dispersion curve of the fundamental mode in small core microstructured fibres (SCMF) is both calculated using a Finite Element Method (FEM) and measured with a low coherence interferometric method. The great sensitivity of the chromatic dispersion to variations of the geometrical parameters of SCMFs (the pitch and the diameter) is pointed out. An excellent agreement is obtained between the numerical and the experimental results over a half micrometer spectral bandwidth [1.1 µm-1.6 µm]

Investigation of passive and active silica-tin oxide nanostructured optical fibers fabricated by " inverse dip-coating " and " powder in tube " method based on the chemical sol-gel process and laser emission

International audienceThis paper presents a study of original nanostructured optical fibers based on the SiO 2-SnO 2-(Yb 3+) system. Two different processes have been developed and compared: the sol-gel chemical method associated to the " inverse dip-coating " (IDC) and the " powder in tube " (PIT) process. The microstructural and optical properties of the fibers are studied according to the concentration of SnO 2. X-Ray Diffraction as well as Transmission Electron Microscopy studies show that SnO 2 crystallizes into the cassiterite phase as nanoparticles with a diameter ranging from 4 to 50 nm as a function of tin oxide concentration. A comparative study highlights a better conservation of SnO 2 into the fiber core with the PIT approach according to the refractive index profile and X-Ray analysis measurement. The attenuation evaluated by the classic cutback method gives respectively values higher than 3 dB/m and 0.2 dB/m in the visible (VIS) and infrared (IR) range for the PIT fiber whereas background losses reach 0.5 dB/m in the VIS range for IDC fibers. The introduction of ytterbium ions into the core of PIT fibers, directly in the first chemical step, leads to a laser emission (between 1050 and 1100 nm) according to the fiber length under 850 nm wavelength pumping. Luminescence studies have demonstrated the influence of the tin oxide nanostructure on the rare earth optical properties especially by the modification of the absorption (850 to 1000 nm) and emission (950 to 1100 nm) by discretization of the bands, as well as on the IR emission lifetime evaluated to 10 µs

Inversion périodique de domaines ferroélectriques par faisceau d'électrons sur Ti:LiNbO3 (Contribution à la réalisation d'un convertisseur en longueurs d'onde indépendant de la polarisation (lambda = 1,55 micro m))

LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

Fabrication of PBG structures by Electron Beam (EB) on LiNbO3

International audienc