Photoinduced stable second-harmonic generation in chalcogenide glasses

We report on photoinduced second-harmonic generation (SHG) in chalcogenide glasses. Fundamental and second-harmonic waves from a nanosecond pulsed Nd:YAG laser were used to induce second-order nonlinearity in chalcogenide glasses. The magnitude of SHG in 20Ge . 20As . 60S glass was 10(4) larger than that of tellurite glass with a composition of 15Nb(2)O(5) . 85TeO(2) (mol.%). Moreover, no apparent decay of photoinduced SHG in 20Ge . 20As . 60S glass was observed after optical poling at room temperature. We suggest that the large and stable value of X-(2) is due to the induced defect structures and large X-(3) of the chalcogenide glasses. (C) 2001 Optical Society of America

Broadband infrared luminescence of bismuth-doped borosilicate glasses

We prepare bismuth-doped borosilicate glasses and the luminescence properties in infrared wavelength region are investigated. Transmission spectrum, fluorescence spectrum and fluorescence decay curve are measured. The glasses exhibit a broad infrared luminescence peaking at 1340nm with the full width at half maximum of about 205nm, and lifetime of 273 mu s when excited by an 808-nm laser diode. The glasses are promising materials for broadband optical amplifiers and tunable lasers.

Infrared broadband emission of bismuth-doped barium-aluminum-borate glasses

We report near infrared broadband emission of bismuth-doped barium-aluminum-borate glasses. The broadband emission covers 1.3 mum window in optical telecommunication systems. And it possesses wide full width at half maximum (FWHM) of similar to 200nm and long lifetime as long as 350 mus. The luminescent properties are quite sensitive to glass compositions and excitation wavelengths. Based on energy matching conditions, we suggest that the infrared emission may be ascribed to P-3(1) --> P-3(0) transition of Bi+. The broad infrared emission characteristics of this material indicate that it might be a promising candidate for broadband optical fiber amplifiers and tunable lasers. (C) 2005 Optical Society of America.

Temperature dependence of femtosecond laser induced refractive index change in Nd3+-doped phosphate glass

We report refractive index change in a femtosecond laser irradiated Nd3+-doped phosphate glass. The effects of annealing temperature on the refractive index change of the glass have been investigated. Absorption spectra of the glass sample before and after femtosecond laser irradiation and subsequent annealing were measured. The results indicate that multiphoton absorption can undertake although there are intrinsic absorption for the glass in irradiation wavelength. The results may be useful for fabrication of three-dimensional integrated optics devices and waveguide laser devices in this glass. (c) 2004 Elsevier B.V. All rights reserved.

Broadband infrared luminescence from Li2O-Al2O3-ZnO-SiO2 glasses doped with Bi2O3

The broadband emission in the 1.2 similar to 1.6 mu m region from Li2O-Al2O3-ZnO-SiO2 ( LAZS) glass codoped with 0.01mol.% Cr2O3 and 1.0mol.% Bi2O3 when pumped by the 808nm laser at room temperature is not initiated from Cr4+ ions, but from bismuth, which is remarkably different from the results reported by Batchelor et al. The broad similar to 1300nm emission from Bi2O3-containing LAZS glasses possesses a FWHM ( Full Width at Half Maximum) more than 250nm and a fluorescent lifetime longer than 500 mu s when excited by the 808nm laser. These glasses might have the potential applications in the broadly tunable lasers and the broadband fiber amplifiers. (c) 2005 Optical Society of America.

GeO2 : Bi, M (M = Ga, B) glasses with super-wide infrared luminescence

Broadband infrared luminescence covering the optical telecommunication wavelength region of 0, E and S bands was observed in GeO2: Bi, M (M = Ga, B) glasses prepared by conventional melting-quenching technique. The luminescence with a maximum at around 1320 nm possesses a full width at half maximum larger than 300 nm and mean fluorescent lifetime longer than 500 mus when excited by an 808 nm-laser. These glasses may have potential applications in widely tunable laser and super-broadband optical amplifier for the optical communications. (C) 2005 Elsevier B.V. All rights reserved.

Investigations on bismuth and aluminum co-doped germanium oxide glasses for ultra-broadband optical amplification

The broadband luminescence covering 1.2-1.6 mu m was observed from bismuth and aluminum co-doped germanium oxide glasses pumped by 808 nm laser at room temperature. The spectroscopic properties of GeO2:Bi,Al glasses strongly depend on the glass compositions and the pumping sources. To a certain extent, the Al3+ ions play as dispersing reagent for the infrared-emission centers in the GeO2:Bi,Al glasses. The broad infrared luminescence with a full width at half maximum larger than 200 nm and a lifetime longer than 200 mu s possesses these glasses with the potential applications in broadly tunable laser sources and ultra-broadband fiber amplifiers in optical communication field. (c) 2005 Elsevier B.V. All rights reserved.

Superbroadband 1310 nm emission from bismuth and tantalum codoped germanium oxide glasses

Near-infrared broadband emission from bismuth-tantalum-codoped germanium oxide glasses was observed at room temperature when the glasses were pumped by an 808 nm laser diode. The emission band covered the 0, E, S, C, and L bands (1260-1625 nm), with a maximum peak at similar to 1310 nm, a FWHM broader than 400 nm, and a lifetime longer than 200 lis. The observed broadband luminescence was attributed to bismuth clusters in the glasses. Bismuth-tantalum-codoped germanium oxide glass might be promising as amplification media for broadly tunable lasers and wideband amplifiers in optical communications. (c) 2005 Optical Society of America.

A novel hollow-core holey fibre with random hole distributions in the cladding

We provide a novel hollow-core holey fibre that owns a random distribution of air holes in the cladding. Our experiments demonstrate that many of the features previously attributed to photonic crystal fibres with perfect arrangement of air holes, in particular, photonic bandgap guidance, can also be obtained in the fibre. Additionally, this fibre exhibits a second guided mode with both the two-lobe patterns, and each pattern is in different colour.