1,721,002 research outputs found
Fundamental differences in the absorption spectra of clustered and isolated ions in EDFAs
No full textThe absorption spectra of clustered and isolated ions in Er-doped fibers have been experimentally studied. The measured significant differences in the absorption characteristics between the two species has considerable implications for the design/assessment of Er-doped fiber amplifiers as well as lasers
Experimental evidence of differences in the absorption spectra of clustered and isolated ions in erbium doped fibers
Full text linkThe absorption spectra of clustered and isolated ions in erbium-doped germanosilicate fibers have been experimentally studied. The ground state absorption spectra broaden as the degree of erbium-ion clustering increases, indicating that the absorption spectra of clustered ions is significantly different from that of the homogeneous ions. This is confirmed by comparing the broadened absorption spectra with the fibre unbleachable loss spectrum; a direct measurement of the clustered ions. This is the first experimental evidence indicating different absorption cross-sections for the two species of ions in germanosilicate glass, an assumption used in the theoretical description of self-pulsing in erbium doped fiber lasers, but in direct contradiction to the pair-induced quenching model widely used to characterise EDFAs
Spectral properties of Er<sup>3+</sup>-doped chalcogenide glasses
No full textLanthanum sulphides glasses formed with sufficient proportions of Ga2S3 constitute a very convenient matrix for rare earth sulphides, and Pr3+-doped Ga2S3:La2S3 (GLS) glasses have been recognized as one of the most promising candidates for fibre amplifiers operating at a wavelength of 1.3µm. In this report, the spectral properties of chalcogenide glass of the molar composition 0.7Ga2S3:0.3La2S3 doped with Er3+ are presented and discussed. Emission and absorption spectra and lifetimes of energy levels have been measured. The 2.7µm emission, as shown below, has been observed from chalcogenide glass for the first time. Radiative and non-radiative transition rates are calculated and compared with the measured lifetimes of interesting energy levels
Intracavity pumped distributed feedback erbium fiber laser
No full textAn intracavity pumping scheme for achieving higher output powers from 1.55µm DFB fiber lasers is proposed and demonstrated. By placing the DFB laser inside the cavity of a Yb3+-fiber laser, up to 3 times higher power has been obtained when compared to the more conventional direct pumping approach
High performance single frequency fiber grating-based Erbium:Ytterbium-codoped fiber lasers
No full textThe device characteristics of Er3+:Yb3+ single frequency fiber lasers are reported. A 5cm long 1550 nm distributed feedback fiber laser with 4 mW output power is shown to have excellent specifications in terms of optical linewidth, signal-to-noise ratio, relative intensity noise, side-mode suppression and polarisation purity. For higher power applications, a 1.5cm single frequency Er3+:Yb3+ grating-based fiber laser with 60 mW output power and a net efficiency of 12% is demonstrated
Neodymium doped gallium lanthanum sulphide glass fibre laser
No full textWe report laser action in a neodymium doped gallium lanthanum sulphide glass fibre at 1.08µm. To our knowledge, this is the first demonstration of laser action in a rare-earth doped chalcogenide glass fibre
High power (60mW) single frequency erbium:ytterbium codoped fiber laser
No full textThe characteristics of a high power Er3+:Yb3+ single frequency fiber laser pumped at 980nm are reported. The device gives 60mW output power with RIN 10MHz and linewidth 500kHz. At low output powers (< 30mW) the slope efficiency is as high as 25%, falling to 12% at higher powers, the saturation behaviour is related to a bottleneck effect due to the finite Yb-Er transfer rate. Improved performance can be obtained using new fibers with an increased rare-earth concentration which show negligible signs of erbium clustering
The effect of oxide on the spectroscopic properties of praseodymium 1.3µm transition in gallium-lanthanum-sulphide glass
No full textThis paper details measurements of 1.0 µm 3H4 to 1G4 absorption and site selective studies of the 1.3µm 1G4 to 3H5 fluorescence of Pr3+-doped gallium lanthanum sulphide (GLS) glasses containing oxide impurities. This oxide produces a second, preferentially-occupied site for the Pr3+ within the GLS, which increases the inhomogeneity of the spectral lines, and decreases the lifetime and the quantum efficiency of the 1G4 level
Spectroscopic and thermal properties of GeS2-based chalcohalide glasses
Full text linkThe low phonon energy of germanium sulphide glasses makes them ideal candidates as hosts for 1.3µm fibre amplifier applications. However, the GeS2 glass host suffers from a major drawback of poor rare-earth ion solubility. In an efficient device, the solubility of Pr ions has to be enhanced, without adversely affecting either the thermal or the spectroscopic properties of the glass. In the present investigation, we report the synthesis and optical properties of modified GeS2-based chalcohalide glasses with excellent thermal characteristics suitable for drawing low-loss optical fibres
Properties of dysprosium doped GaLaS fibre amplifiers operating at 1.3µm
No full textIn light of the recent progress on the fabrication of GaLaS fibres we have modelled the performance of dysprosium doped GaLaS fibre amplifiers operating at 1.3µm. Based on experimental data, we find the incorporation of a co-dopant (terbium) in the fibre core significantly shortens the optimum amplifier length from >30m to ~3m. Such a device may be practical given the fibre losses currently achieved in GaLaS fibres
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