Nonsaturable absorption in alumino-silicate bismuth-doped fibers

We report an experimental and theoretical investigation of fluorescence decay and transmission coefficient at ∼1 μm pumping for a series of bismuth (Bi) doped alumino-silicate fibers with different concentrations of Bi centers. By modeling the experimental data, we show that the excited-state absorption (ESA) and up-conversion (UC) processes are responsible for a growth of nonsaturable absorption and deviation from exponential the fluorescence decay in the fibers with an increase in Bi centers content. Assuming that Bi centers ensemble is composed of subsystems of single and paired centers, and an increase in partial weight of the latter with a Bi centers concentration growth, we can successfully explain the experimental data. Also, these assumptions allow us to estimate the constants characterizing the ESA and both homogeneous and inhomogeneous UC processes in the fibers

Excited-state absorption in erbium-doped silica fiber with simultaneous excitation at 977 and 1531 nm

We report a study of the excited-state absorption (ESA) in erbium-doped silica fiber (EDF) pumped at 977 nm, when the fiber is simultaneously excited by signal radiation at 1531 nm. We show, both experimentally and theoretically, that ESA efficiency at 977 nm gets strongly enhanced only in the presence of signal power. Experimentally, this conclusion is supported through the detection of upconversion emission, a “fingerprint” of the ESA process, and through the measurements of the EDF nonlinear transmission coefficient for the pump wavelength, which is sensitive to the ESA value. It is shown that the experimental data are precisely modeled with an advanced five-level Er3+ model developed for the [email protected] [email protected]

Upconversion assisted self-pulsing in a high-concentration erbium doped fiber laser

We report results on experimental and theoretical characterisation of self-pulsing in high concentration erbium doped fibre laser which is free from erbium clusters. Unlike previous models of self-pulsing accounting for pair-induced quenching (PIQ) on the clustered erbium ions, new model has been developed with accounting for statistical nature of the excitation migration and upconversion and resonance-like pumpto-signal intensity noise transfer. The obtained results are in a good agreement with the experimental data

Transform-limited pulses generated by an actively Q-switched distributed fiber laser

A single-mode, transform-limited, actively Q-switched distributed-feedback fiber laser is presented, based on a new in-line acoustic pulse generator. Our technique permits a continuous adjustment of the repetition rate that modulates the Q factor of the cavity. Optical pulses of 800 mW peak power, 32 ns temporal width, and up to 20 kHz repetition rates were obtained. The measured linewidth demonstrates that these pulses are transform limited: 6 MHz for a train of pulses of 10 kHz repetition rate, 80 ns temporal width, and 60 mW peak power. Efficient excitation of spontaneous Brillouin scattering is demonstrated.Fil: Cuadrado Laborde, Christian Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; Argentina. Universidad de Valencia; EspañaFil: Pérez Millán, P.. Universidad de Valencia; EspañaFil: Andrés, M. V.. Universidad de Valencia; EspañaFil: Díez, A.. Universidad de Valencia; EspañaFil: Cruz, J. L.. Universidad de Valencia; EspañaFil: Barmenkov, Yu. O.. Centro de Investigaciones en Óptica; Méxic

Development of large-core Yb(2)O(3)-doped yttria-alumino-silicate nano-particles based optical fibers

Yb(2)O(3) doped high yttrium alumino-silicate nano-particles based D- and pentagonal (P-) shaped optical fibers having core diameter around 30.0-35.0 mu m have been obtained through the conventional modified chemical vapour deposition (MCVD) process and solution doping (SD) technique using thin wall tubes of CSA, around 58-60 mm(2), followed by enlargement of the inner deposition surface area under suitable pressurization. The process parameters at the different stages of preform fabrication have been optimized in order to obtain the uniform distributions of Al, Yb, and Y along the core diameter. Nano-particles were synthesized under soaking of the porous phospho-silicate core layer in a solution of optimum strength of ytterbium chloride, yttrium chloride, and aluminum chloride. The size of nano-particles was maintained within 5-10 nm under doping of 0.2 mol.% of fluorine. The EDX data reveal that the nano-particles are rich in yttria-alumino-silicate phase and dispersed uniformly. The novelty of this technique involves the direct synthesis of rare-earth doped phase-separated nano-particles within the large core of optical fiber. The critical fabrication parameters of the process along with the nano-structuration results and spectroscopic properties are highlighted

Fabrication and characterization of new Yb-doped zirconia-germano-alumino silicate phase-separated nano-particles based fibers

New zirconia-germano-alumino silicate, nano-particles based, Ytterbium doped fibers are obtained through the conventional modified chemical vapour deposition and solution doping techniques. The start fiber preforms are characterized by means of electron micro probe, energy dispersive x-ray, and electron diffraction analyses, revealing the presence of phase-separated nano-sized Ytterbium-rich areas in the core, while the final fibers are inspected in the sense of spectroscopy and laser properties. (C) 2011 Optical Society of Americ

Yb-doped yttria-alumino-silicate nano-particles based optical fibers: Fabrication and characterization

An efficient method to fabricate transparent glass ceramic fibers containing in-situ grown Yb(3+) doped oxide nano-particles based on yttria-alumino-silicate glass is presented. These large-mode area Yb(3+) doped fibers having a core diameter around 25.0 mu m were drawn by a proper control over the involved process parameters; by this, the size of nano-particles was maintained within 5-10 nm. The main spectroscopic and laser properties of the fabricated fibers along with the nano-structuration results are reported. These results reveal that the developed method offers new scopes for the contemporary Yb(3+) fiber based devices. (C) 2011 Elsevier Ltd. All rights reserved