Showing papers by "E. M. Dianov published in 2010"
TL;DR: In this paper, the NIR-emitting optical centers in Bi2O3-doped MgO-Al2O-3-SiO2 glass were shown to be bismuth dimers formed in a reversible endothermic redox chemical reaction.
Abstract: The NIR-emitting optical centers in Bi2O3-doped MgO–Al2O3–SiO2 glass were shown to be bismuth dimers formed in a reversible endothermic redox chemical reaction. The reaction enthalpy and the effective dimer charge were determined. It was also brought out that the red (∼720 nm) emission band originates from the centers that are quite different from IR-emitting ones.
46 citations
TL;DR: In this article, bismuth-doped fiber lasers operating at the wavelength of 1179 nm with an optical efficiency of up to 28% were realized, while the unsaturable absorption increases with increasing the small-signal absorption.
Abstract: In this study, bismuth-doped fiber lasers operating at the wavelength of 1179 nm with an optical efficiency of up to 28% are realized. The fiber gain upon 1-?m pumping declines, while the unsaturable absorption increases with increasing the small-signal absorption. We conclude that up-conversion and excited-state absorption are responsible for limiting the efficiency of such lasers.
46 citations
TL;DR: The pulse evolution in Bi-doped soliton fiber laser with slow and fast saturable absorber has been studied both experimentally and numerically and the pulse dynamics within the Bi fiber laser cavity have been investigated.
Abstract: The pulse evolution in Bi-doped soliton fiber laser with slow and fast saturable absorber has been studied both experimentally and numerically. Semiconductor saturable absorbers with balanced slow and fast absorption recovery mechanisms exhibit a bi-temporal recovery dynamics which permits both reliable start-up of passive mode-locking and short pulse generation and stabilization. The pulse dynamics within the Bi fiber laser cavity have been investigated.
22 citations
TL;DR: In this paper, the spectral properties of optical fibres with bismuth-doped aluminosilicate glass core are investigated on the basis of a molecular orbital theory and a Schrodinger equation solution.
Abstract: The spectral phenomena in optical fibres with bismuth-doped aluminosilicate glass core are explicated on the basis of a molecular orbital theory and of a Schrodinger equation solution, taking into account the exchange, spin–orbit and crystal field interactions of s, p and d electrons of M atoms (M signifies Bi, Sb, Pb, Sn, In, Te, etc) with ligand orbits of environmental B atoms (B signifies O, S, Se, etc). Energy level diagrams and selection rules of transitions between molecular orbital states of s and p electrons of MBm molecule permit us to determine the energies of the main spectral transitions of absorption and luminescent spectra and their correspondence with experimental spectra of different types of optical fibres is obtained.
8 citations
TL;DR: In this paper, the authors measured the refractive index of crystalline GaAs by the method of interference refractometry in the wavenumber range from 10?500 to 540?cm?1 (or the wavelength range from 0.9 to 18.6??m) with a resolution of 0.61??m.
Abstract: The refractive index of crystalline GaAs is measured by the method of interference refractometry in the wavenumber range from 10?500 to 540?cm?1 (or the wavelength range from 0.9 to 18.6??m) with a resolution of 0.1?cm?1. The measurement results are approximated by the generalized Cauchy dispersion formula of the 8th power. Spectral wavelength dependences of the first- and second-order derivatives of the refractive index are calculated, and the zero material dispersion wavelength is found to be ?0 = 6.61??m. Using three GaAs plates of different thicknesses we managed to raise the refractive index measurement accuracy up to 4 ? 10?4 or 0.02%, being nearly by an order of magnitude better than the data available.
8 citations
TL;DR: In this article, the extinction coefficient of Ni2+ in tellurite glasses has been investigated at wavelengths from 450 to 2700 nm, and the spectral dependence of the extinction coefficients has been obtained.
Abstract: The absorption spectra of (TeO2)0.78(WO3)0.22 glasses containing 0.01–1.0 wt % NiO have been measured at wavelengths from 450 to 2700 nm, and the spectral dependence of the extinction coefficient of Ni2+ in the glasses has been obtained. In the absorption bands centered at 810 and 1320 nm, the extinction coefficient is 20.2 ± 0.8 cm−1 (870 ± 35 dB/(km ppmw)). According to the spectral range of its absorption and its extinction coefficient, nickel is a strongly absorbing impurity in tellurite glasses. The present results can be used to formulate sound nickel concentration limits in tellurite glasses for fiber-optic applications.
5 citations
TL;DR: In this article, the size distribution of silica glass particles in the fabrication of heavily doped germanosilicate glass fiber preforms by modified chemical vapor deposition (MCVD) at different Freon 113 concentrations in the gas mixture was studied.
Abstract: We have studied the size distribution of silica glass particles in the fabrication of heavily doped germanosilicate glass fiber preforms by modified chemical vapor deposition (MCVD) at different Freon 113 concentrations in the gas mixture. The addition of Freon 113 to the gas mixture is shown to reduce the particle size in the deposited core glass layer and the optical loss in the fiber. A mechanism is proposed which accounts for the effect of the initial particle size in the core glass layer on the anomalous scattering and total optical loss in heavily doped step- and graded-index fibers.
4 citations
21 Mar 2010
TL;DR: In this paper, the authors present the results on the development of Bi-doped fiber lasers and amplifiers for the telecom window of 1300-1500nm in particular, and present a detailed analysis of the results.
Abstract: Bi-doped fibers are a promising medium for lasers and amplifiers in the 1150-1600nm wavelength range. We present the results on the development of Bi-doped fiber lasers and amplifiers for telecom window of 1300-1500nm in particular.
3 citations
TL;DR: In this article, a 10-nm-thick sacrificial layer of ZnMgSSe and a 20-nmthick stressed bilayer of ZnsSe/ZnSe were grown by molecular-beam epitaxy on GaAs substrates.
Abstract: Nanostructures consisting of a 10-nm-thick sacrificial layer of ZnMgSSe and a 20-nm-thick stressed bilayer of ZnSSe/ZnSe were grown by molecular-beam epitaxy on GaAs substrates Upon removal of the sacrificial layer by selective etching, multiwall ZnSSe/ZnSe microtubes were formed
2 citations
16 May 2010
TL;DR: In this article, the luminescence, gain and lasing properties of Bi-doped fibers of different core composition are discussed, and the performance of a Bi-Doped fiber amplifier operating in the wavelength range 1300-1500 nm with peak gain > 20dB is demonstrated.
Abstract: We will discuss the luminescence, gain and lasing properties of Bi-doped fibers of different core composition. Bi-doped fiber amplifiers operating in the wavelength range 1300–1500 nm with peak gain >20dB are demonstrated.
2 citations
16 May 2010
TL;DR: In this article, the Rod-in-Tubes method was used to fabricate silicon-core optical fibers with losses of 11-12 dB/cm in a wavelength range of 1.5-6.7 µm.
Abstract: Silicon-core optical fibers were fabricated by the “rod-in-tube” method. Optical losses were reduced to the level of 11–12 dB/cm in a wavelength range of 1.5–6.7 µm owing to a postdrawing treatment similar to zone melting.
16 May 2010
TL;DR: In this paper, a multimode graded-index fluorine-doped fibers with a record value of −0.0115 (NA∼0.185) were fabricated and tested at high temperature (up to 300°C) in hydrogen atmosphere (50 atm).
Abstract: Multimode graded-index fluorine-doped fibers with a record (for the MCVD method) value of the refractive index difference of −0.0115 (NA∼0.185) were fabricated and tested at high temperature (up to 300°C) in hydrogen atmosphere (50 atm).