Pluie de solitons dans un laser à fibre co-dopée Er:Yb en forme de huit

Nous rapportons ici l\u27observation expérimentale d\u27un comportement collectif d\u27un ensemble de soliton, appelé pluie de solitons, dans un laser à fibre en forme de huit avec un miroir à boucle non linéaire (NOLM). Cette dynamique non linéaire a été précédemment observée dans un laser à fibre verrouillé passivement par la technique de rotation de polarisation non linéaire. A partir d\u27un fond continu, des solitons se créent et dérivent vers la phase condensée de plusieurs solitons. L\u27observation de cette dynamique tend à renforcer l\u27idée de l\u27universalité du comportement collectif des solitons. 

Soliton pattern formation in figure-of-eight laser

We investigate the soliton pattern formation in an erbium-doped figure-of-eight double-clad fiber laser. The mode-locking is realized with a nonlinear amplifying loop mirror. Different soliton complexes have been obtained similar to those obtained when the mode-locking is achieved through the nonlinear polarization rotation technique

The Mae I assay for scoring atrazine resistance is codon-usage dependent in legumes

A research experiment on herbicide atrazine usages as observed out in Zimbabwe.Nine different cowpea varieties were grown and total deoxyribonucleic acid (DNA) isolated from the young leaves. This DNA was used to amplify a 291 base pair fragment that contained codon 264 of the psb A gene. The primers used were designed based on the soybean psb A gene sequence. The 291 base pair fragment was digested with the restriction enzyme Mae I to assay for sensitivity/resistance to atrazine using a published method. When Mae I did not cut the 291 base fragment, the whole gene was amplified by the polymerase chain reaction, cloned into pBSK+ll (Stratagene, CA, USA) and sequenced around codon 264. Codons 263 and 264 were found to be GCA and AGT respectively. UWGCG and BLASTsearchesofthepsbAgenesequences in the databases confirmed that Mae I has a recognition site that overlaps with codons 263 and 264 in some legumes but not in others. The Mae I assay used by Cheung and co-workers is therefore not universal but depends on codon usage in legumes

Harmonic dissipative soliton resonance square pulses in an anomalous dispersion passively mode-locked fiber ring laser

We demonstrate the generation of dissipative soliton resonance square pulses from a co-doped Er:Yb double-clad fiber ring laser operating in an all anomalous dispersion regime. The obtained pulses have a repetition rate of 672 kHz and a pulse energy of 409 nJ. By carefully adjusting the polarization controllers while increasing the pump power, the square pulse can split into a series of identical equally spaced smaller square pulses up to the 13th harmonic of the fundamental repetition frequency. The average output energy of the square pulses follows a scaling law versus the harmonic orde

Control of soliton pattern through continuous external injection

The effect of an external continuous wave (cw) on the operating regime of a passively mode-locked double-clad fiber laser, operating in the anomalous dispersion regime, is experimentally investigated. Starting from different soliton distributions, we demonstrate that, under specific conditions, the cw signal forces the principal laser to operate in harmonic mode-locking regime

Passive mode-locking of a 10 W double-clad fiber laser

We report experimental observation of bound states of soliton in passively mode-locked erbium-doped double-clad fiber laser. Operating in the anomalous dispersion regime with a double-clad fiber 10W amplifier allows generation of up to several thousands of solitons per round trip. By increasing the pumping power we pass from one bound state to several separated bound states. The bound states self-organize them leading to harmonic mode-locking of soliton crystals

Broadly peak power and pulse width tunable dissipative soliton resonance generation in Figure-of-Eight fiber laser

We experimentally demonstrate a broadlytunable dissipative soliton resonancedual-amplifier figure-of-eight fiber laseremission.The peak power is tuned continuously from 8.8to 41.4Wby the first amplifier andpulse width from 84 to 416 nsby the second one

Spectral dynamics of square pulses in passively mode-locked fiber lasers

We investigate experimentally and numerically the spectral dynamics of square pulses generated in passively mode-locked fiber lasers under the dissipative soliton resonance. The features of the transition from the single-peak spectral profile to the doublet spectrum with increasing pump power are studied. The used master equation takes into account the gain saturation, the quadratic frequency dispersion of the gain and the refractive index, and the cubic-quintic nonlinearity of the losses and refractive index. Experimental data are obtained for an Er:Yb-doped fiber ring laser. The theoretical and experimental results are in good agreement with each other