Search results for "fiber"
showing 10 items of 2343 documents
Radiation-induced defects in fluorine-doped silica-based optical fibers: Influence of a pre-loading with H2
2009
International audience; We investigated the effects of 10-keV X-ray radiation on the transmission properties of F-doped optical fibers in the 200–850 nm range of wavelengths (1.5–6 eV). We also studied the influence of pre-loading this kind of fibers with hydrogen on its radiation sensitivity. Our results showed that, for our experimental conditions (pre-treatment with H2 several months before irradiation with diffusion of all the H2 out the fiber core and cladding before X-ray exposure), this pre-treatment increases the radiation-induced attenuation in the ultraviolet part (200–300 nm) of the spectrum. A previous H2-loading has no influence at greater wavelengths. The nature of the radiati…
Design rules for nonlinear spectral compression in optical fibers
2016
International audience; We present comprehensive design rules to optimize the process of spectral compression arising from nonlinear pulse propagation in an optical fiber. Extensive numerical simulations are used to predict the performance characteristics of the process as well as to identify the optimal operational conditions within the space of system parameters. It is shown that the group-velocity dispersion of the fiber is not detrimental and, in fact, helps achieve optimum compression. We also demonstrate that near-transform-limited rectangular and parabolic pulses can be generated in the region of optimum compression.
On recent progress in all-fibered pulsed optical sources from 20 GHz to 2 THz based on multiple four wave mixing approach
2009
International audience; In this paper, we report recent progress on the design of all-fibered ultra-high repetition-rate pulse sources for telecommunication applications around 1550 nm. Based on the nonlinear compression of an initial beat-signal in optical fibers through a multiple four-wave mixing process, we theoretically and experimentally demonstrate that this simple technique allows an efficient and accurate design of versatile pulse sources having repetition rates and pulse durations ranging from 20 GHz up to 2 THz and from 10 ps up to 110 fs, respectively.
Nonlinear sculpturing of optical pulses with normally dispersive fiber-based devices
2018
International audience; We present a general method to determine the parameters of nonlinear pulse shaping systems based on pulse propagation in a normally dispersive fiber that are required to achieve the generation of pulses with various specified temporal properties. The nonlinear shaping process is reduced to a numerical optimization problem over a three-dimensional space, where the intersections of different surfaces provide the means to quickly identify the sets of parameters of interest. We also show that the implementation of a machine-learning strategy can efficiently address the multi-parameter optimization problem being studied.
Second zero dispersion wavelength measurement through soliton self-frequency shift compensation in suspended core fibre
2008
International audience; A simple experimental technique to evaluate the second zero dispersion wavelength of very small core microstrutured fibres is described. Based on the effect of soliton self-frequency shift and its subsequent compensation in the vicinity of the second zero dispersion. the proposed method is applied to both standard and suspended core microstructured fibres by simply measuring the frequency stabilised soliton spectrum, avoiding any calculation and knowledge of any experimental parameters.
Influence of fluorine on the fiber performance studied through the NBOHC-related 1.9 eV microluminescence
2012
International audience; The distribution of Non Bridging Oxygen Hole Centers (NBOHC) in Fluorine doped optical fibers was investigated by confocal microluminescence spectroscopy monitoring the characteristic 1.9 eV luminescence band. The results show that these defects are generated by the fiber drawing and their concentration further increases after γ irradiation. The NBOHC profile along the fiber is anticorrelated to the fluorine content. This finding agrees with the role of fluorine in the fiber toughness and is discussed from the microscopic point of view on the basis of previous works.
Spectroscopic studies of the origin of the radiation-induced degradation in phosphorous-doped optical fiber and preforms
2010
In this paper, we study the radiation-induced point defects related to the phosphorus element that is commonly used to improve the optical properties of silica-based glasses but is responsible of a dramatic increase in their radiation sensitivity. To this aim, the influence of x-ray irradiation on prototype phosphorus-doped canonical fibers and their related preforms was investigated by in situ radiation induced attenuation (RIA), optical absorption, and electron spin resonance (ESR) spectroscopy. The RIA spectra in the (1.5-5 eV) range, can be explained by the presence of at least three absorption bands induced by radiation exposure. Additionally the X-dose dependence of such bands was stu…
X-ray irradiation effects on a specific multistep Ge-doped fiber
2010
International audience; The study of point defects generation in optical fibers plays an important role with regards to their use and application in different domains. Their design and elaboration processes (dopants type, concentration, refractive index profile, drawing conditions...) govern their responses and more generally their radiation hardness [1]. In this work we investigated, the influence of 10 keV X-ray irradiations on a set of specific germanosilicate optical fibers elaborated from the same preform at different drawing conditions. The germanium doping levels along the fiber core diameter was specifically designed to follow a two-step distribution in order to highlight the Ge-con…
Radiation Effects on Silica-Based Preforms and Optical Fibers - I: Experimental Study with Canonical Samples
2008
International audience; The influence of the F- and Ge-doping on the fiber radiation responses is investigated through online measurements of the UV-visible induced attenuation and spectroscopic studies (ESR, confocal microscopy of luminescence) on prototype samples
Spatiotemporal beam shaping in nonlinear multimode fibers
2018
Kerr beam self-cleaning in graded-index multimode fibers is accompanied by power-dependent temporal pulse reshaping. We explore the complex nonlinear dynamics with a single long pulse, where the optical power is continuously varied across its profile.