Polarization properties of elliptical core non-hexagonal symmetry polymer photonic crystal fibre

In this paper, polarization properties and propagation characteristics of polymer photonic crystal fibres with elliptical core and non-hexagonal symmetry structure are investigated by using the full vectorial plane wave method. The results how that the birefringence of the fibreis induced by asymmetries of both the cladding and the core. Moreover, by adjusting the non-symmetrical ratio factor of cladding eta from 0.4 to 1 in step 0.1, we find the optimized design parameters f the fibre with high birefringence and limited polarization mode dispersion, operating in a single mode regime at an appropriate wavelength range. The range of wavelength approaches the visible and near-infrared which is consistent with the communication windows of polymer optical fibres.

Generation of 207-femtosecond pulses from a ytterbium figure-of-eight fibre laser

We report the generation of 207-fs pulses with 1.2mW average power at 1036 nm directly from a passively mode-locked Yb-doped fibre laser with a nonlinear optical loop mirror for mode-locking and pairs of diffraction gratings for intracavity dispersion compensation. These results imply a 4-fold reduction in pulse duration over previously reported figure-of-eight cavity passively mode-locked Yb-doped fibre lasers. Stable pulse trains are produced at the fundamental repetition rate of the resonator, 24.0MHz. On the other hand, this laser offers a cleaner spectrum and greater stability and is completely self-starting.

Broadly tunable SOA-based active mode-locked fibre ring laser by forward injection optical pulse

We present a broadly tunable active mode- locked. bre ring laser based on a semiconductor optical ampli. er ( SOA), with forward injection optical pulses. The laser can generate pulse sequence with pulsewidth about 12 ps and high output power up to 8.56dBm at 2.5 GHz stably. Incorporated with a wavelength- tunable optical bandpass. lter, the pulse laser can operate with a broad wavelength tunable span up to 37nm with almost constant pulsewidth. A detailed experimental analysis is also carried out to investigate the relationship between the power of the internal cavity and the pulsewidth of the output pulse sequence. The experimental con. guration of the pulse laser is very simple and easy to setup with no polarization- sensitive components.

Casting preforms for microstructured polymer optical fibre fabrication

A monolithic structured polymer preform was formed by in-situ chemical polymerization of high-purity MMA monomer in a home-made mould. The conditions for fabrication of the preforms were optimized and the preform was drawn to microstructured polymer optical fibre. The optical properties of the resultant elliptical-core fibre were measured. This technique provides advantages over alternative preform fabrication methods such as drilling and capillary stacking, which are less suitable for mass production. (c) 2006 Optical Society of America.

Sol-gel matrix modified microstructured optical fibre towards a fluoride sensitive optical probe

In this article, we report an optical fluoride probe based on microstructured polymer optical fibers (MPOFs) which is modified with morin-Al complex doped silica gel film. This probe is fabricated by sol-gel fluxion coating process. Sol solution doped with morin-Al is directly inhaled into array holes of MPOF and then forms morin-Al-gel matrix film in them. The sensing probe shows different fluorescence intensity to different fluoride ion concentrations in the aqueous solution. The range of response is 550 mmol/L, under the condition of pH 4.6. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

Intense green upconversion emission in Tb3+/Yb3+ co-doped alumino-germano-silicate optical fibers

Tb/Yb共掺的石英光纤的上转换绿光发光研究，研究了最佳浓度配比和发光机理。

Green's function of a two-dimensional interacting electron gas in a perpendicular magnetic field

It is rigorously proved that the Green's function of a uniform two-dimensional interacting electron gas in a perpendicular magnetic field is diagonal with respect to single-particle states in the Landau gauge. The implication of this theorem is briefly discussed.

High electrical-to-green efficiency high stability intracavity-frequency-doubled Nd:YAG-LBO QCW 532 nm laser with a straight cavity

An electrical-to-green efficiency of more than 10% was demonstrated by intracavity-frequency-doubling a Q-switched diode-side-pumped Nd:YAG laser with a type II lithium triborate (LBO) crystal in a straight plano-concave cavity. An average power of 69.2 W at 532 nm was generated when electrical input power was 666 W. The corresponding electrical-to-green conversion efficiency is 10.4%. To the best of our knowledge, this is the highest electrical-to-green efficiency of second harmonic generation laser systems with side-pumped laser modules, ever reported. At about 66 W of green output power, the power fluctuation over 4 hours was better than +/-0.86%.