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A ray dynamical approach is developed for the study of large-core asymmetric step index fibres (SIF), especially those made from chalcogenide glasses (ChGs) which can exhibit very high refractive index, large numerical aperture, and which are transparent at mid-infrared wavelengths. The model allows for deformations of the SIF away from concentric circular structures, and for the light rays captured...
Chalcogenide glass fibres have been demonstrated as a suitable medium for the realisation of spontaneous emission sources for mid-infrared photonics applications with a particular emphasis on sensor technology. Such sources give a viable alternative to other solutions due to their potentially low cost, high reliability and robustness when pumped using commercially available semiconductor lasers. We...
We develop a model of a terbium (111) ion doped selenide chalcogenide glass fibre source that provides spontaneous emission within the mid-infrared (MIR) wavelength range. We use two numerical algorithms to calculate the solution and compare their properties.
Much effort has been devoted to the study of glasses that contain the chalcogen elements (sulfur, selenium and tellurium) for photonics' applications out to MIR wavelengths. In this paper we describe some techniques for determining the refractive index dispersion characteristics of these glasses. Knowledge of material dispersion is critical in delivering step-index fibres including with high numerical...
In this contribution a multiwavelength erbium ring laser is presented. The multiwavelength operation isachievedby using a novel in-line Mach-Zehnder (MZ) fibre interferometer based on multicore microstructured fibre (MC-MOF).The MZ interferometer acts as a periodic spectral filter. The modal properties of the MC-MOF are analysed using the finite difference method. Dual wavelength operation is demonstrated...
We discuss the numerical modelling of lanthanide-ion doped chalcogenide glass fibre lasers for operation in the mid-infrared wavelength region. We extract the modelling parameters from emission and absorption measurements using Judd-Ofelt and McCumber theory. Numerical algorithms are developed based on the experimentally extracted fibre parameters. The simulation results predict lasing with slope...
Fiber lasers are a fast growing class of lasers due to their reliability, efficiency and flexibility. This has made fiber lasers a versatile tool for manufacturing, sensing and healthcare, not forgetting the contribution of Erbium-doped amplifiers to optical communications. Yet available wavelengths by direct emission are quite restricted to the visible and near infrared wavelength interval (500 nm...
The mid-infrared (MIR) spans the 3 – 25 µm wavelength range. Rare-earth-ion doped selenide-chalcogenide glasses are being developed for direct-emission MIR fibre lasers. The true Pr3+ absorption cross-section in the 3.5 – 6 µm wavelength region of a Pr3+-doped (500 ppmw of Pr3+ i.e. 9.47×1019 Pr3+ ions cm−3) GeAsGaSe host-glass is presented, after numerically removing the underlying, extrinsic vibrational...
We present a study of mid-infrared photoluminescence emitted from Tb3+:GeAsGaSe chalcogenide bulk glass and fibre. Absorption and emission cross-sections were calculated based on measured results. The decay characteristic related to the potential laser transition 7F5 → 7F6 has been measured and investigated. The observed high values of emission and absorption cross-sections and long lifetime from...
We consider the modelling and design of high power ZBLAN glass based erbium (III) doped fibre lasers operating in the Q-switched regime. The detailed description of all models used is given. The results are calculated for a standard set of modelling parameters used in the literature, which correspond to a commercially available erbium doped ZBLAN fibre. We apply a time domain method which uses a steady...
We discuss the modelling and design of mid-infrared fibre lasers for realisation in a chalcogenide glass host doped with lanthanide ions. Three lanthanide dopant ions are considered: terbium, dysprosium and praseodymium. The laser configuration exploits the advantages of a cascade lasing scheme, which allows for a reduction in both the side effects of the long lifetime of the lower lying state and...
In this contribution we present the sensing capabilities of a novel N-path Mach-Zehnder interferometer (MZI) that relies on a multicore microstructured optical fibre (MC-MOF) connected between two sections of the standard single mode fibre. The modal properties of the MC-MOF structure are analyzed experimentally by measuring near field profiles. The dependence of the N-path MC-MOF MZI sensitivity...
Lanthanide ion doped glass materials find many applications in photonics. In recent years a particular attention has been drawn to lanthanide ion doped low phonon energy glasses and their potential application as amplifiers and lasers delivering mid-infrared coherent light. We present a comprehensive study of the photoluminescence measured from chalcogenide glass samples doped with praseodymium ions...
Chalcogenide glasses are promising materials for mid-infrared (MIR) fibre optic applications i.e. 3–25 μm wavelength. Their low phonon energy is attractive not only for passive mid-IR transmission fibre-conduits but also for active fibre. For the latter, rare earth (RE-)-ion doped chalcogenide glasses have been investigated, as direct emission mid-IR fibre lasers. The quality of the chalcogenide glass...
In this article a novel highly- birefringent erbium-doped microstructured optical fiber is presented. The modal properties of the structure are analyzed numerically using a fully vectorial finite difference method. The emission properties of the structure have also been investigated. The emission at 1550 nm has been measured. The realised fiber can find potential applications in metrology or telecommunication...
This paper examines some of the factors affecting the brightness of high-power tapered lasers, including bleaching of the ridge waveguide and mismatch between the taper and the beam diffraction angle, which excite high-order modes.
In this paper we present a novel, highly birefringent, microstructured optical fiber structure doped with neodymium. To our best knowledge it is the first report of a rare earth doped fiber with so high birefringence. The modal properties of the structure were analyzed using the full vectorial finite difference method. The emission spectra were also measured. Laser action in the simplest configuration,...
The presentation gives an account of recent developments in the modelling of chalcogenide glass based lanthanide doped fibre lasers for the mid-infra-red (MIR) wavelength range. The particular lanthanide elements considered include dysprosium, praseodymium and terbium. Both classical 3 level lasing systems and cascade lasing systems are considered, and their properties compared. Steady state and pulsed...
Results of theoretical and experimental studies of a photonic crystal fiber erbium doped ring laser are presented. Modeling parameters have been measured directly or calculated for the photonic crystal fiber analyzed. The simulations were carried out by solving in a self consistent manner the propagation and rate equations.
We present a photonic crystal fibre based, erbium doped, polarization maintaining, near infrared, fibre laser operating in a ring cavity. Stable narrow bandwidth operation of the developed fibre laser was observed in a laser ring configuration. In the paper we present the description of the laser design process and of the experimental characterisation and validation.
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