High-energy dissipative solitons generation from a large normal dispersion Er-fiber laser.

We report on a passively mode-locked erbium-doped fiber laser featuring a large normal dispersion and emitting high-energy dissipative solitons. Mode-locking is stabilized by the combined actions of a high nonlinearity amplitude modulator and a narrow band spectral filter. The laser routinely delivers highly chirped pulses with more than 38 nJ energy that can be compressed down to 700 fs duration using bulk gratings. Numerical simulations confirm the experimental results and reveal the self-similar pulse evolution along the normal dispersion fibers included inside the cavity.

High power all-fibered femtosecond master oscillator power amplifier at 1.56 µm.

Direct amplification of output from chirped pulse oscillator (CPO) to 3.3 W of average power (pulse energy of 118 nJ in 20 ps pulse duration before compression) was achieved in a properly designed cladding pumped large mode area Er-doped fiber. Various configurations of CPO cavity with different FWHM of output spectrum and pulse duration were investigated. Fourier limit compression with 480 fs pulse duration and 32 kW peak power has been obtained for pulses with 14.8 nm FWHM spectrum. Subsequent nonlinear compression in a standard SMF-28 fiber yielded pulses as short as 145 fs.

High power dissipative soliton in an Erbium-doped fiber laser mode-locked with a high modulation depth saturable absorber mirror.

We report on a passively mode-locked erbium-doped fiber laser, using a high nonlinear modulation depth saturable absorber mirror, in a Fabry-Perot cavity. A segment of dispersion compensation fiber is added inside the cavity in order to build a high-positive dispersion regime. The setup produced highly chirped pulses with an energy of 1.8 nJ at a repetition rate of 33.5 MHz. Numerical simulations accurately reflect our experimental results and show that pulse-shaping in this laser could be interpreted as producing 'dissipative solitons'.

Phase-amplitude characterization of a high-repetition-rate quantum dash passively mode-locked laser.

We apply a novel phase-amplitude characterization method to a one-section quantum dash-based passively mode-locked laser at a 42.2 GHz repetition rate. The method relies on the measurement of the spectral phase of the longitudinal modes by the successive analysis of the correlation signal of a group of three adjacent modes. It provides both the temporal shape of the intensity and the phase of the emitted signal. A pulse of 1.5 ps of width is measured, and a pedestal is exhibited. Extinction ratio limitation is explained by investigating the origin of this pedestal. The accuracy of the method is estimated by comparing the measured autocorrelation signal and the calculated one from the phase analysis.

All-optical extinction-ratio enhancement of a 160 GHz pulse train by a saturable-absorber vertical microcavity.

A vertical-access passive all-optical gate has been used to improve the extinction ratio of a 160 GHz pico-second pulse train at 1555 nm. An extinction ratio enhancement of 6 dB is observed within an 8 nm bandwidth. Such a device is a promising candidate for low-cost all optical reamplication and reshaping (2R) regeneration at 160 Gbits/s.

Demonstration of optically controlled data routing with the use of multiple-quantum-well bistable and electro-optical devices.

We present experimental results on a 1-to-64-channel free-space photonic switching demonstration system based on GaAs/GaAlAs multiple-quantum-well active device arrays. Two control schemes are demonstrated: data transparent optical self-routing usable in a packet-switching environment and direct optical control with potential signal amplification for circuit switching. The self-routing operation relies on the optical recognition of the binary destination address coded in each packet header. Address decoding is implemented with elementary optical bistable devices and modulator pixels as all-optical latches and electro-optical and gates, respectively. All 60 defect-free channels of the system could be operated one by one, but the simultaneous operation of only three channels could be achieved mainly because of the spatial nonhomogeneities of the devices. Direct-control operation is based on directly setting the bistable device reflectivity with a variable-control beam power. This working mode turned out to be much more tolerant of spatial noises: 37 channels of the system could be operated simultaneously. Further development of the system to a crossbar of N inputs and M outputs and system miniaturization are also considered.

[Pathologic features of a case of systemic brucellosis due to Brucella melitensis biovar 3 in a chamois (Rupicapra rupicapra)]. / Etude anatomopathologique d'un cas de brucellose généralisée chez le chamois (Rupicapra rupicapra) à Brucella melitensis biovar 3.

A case of systemic brucellosis caused by Brucella melitensis biovar 3 was identified in a chamois (Rupicapra rupicapra) in the southern French Alps. Clinical signs included bilateral orchiepididymitis and keratoconjunctivitis, polyarthritis, and neurological signs; pathological findings confirmed an ulcerative keratitis, orchiepididymitis with calcified or necrotic foci and serofibrinous and hemorrhagic polyarthritis. The kidney cortex showed calcified nodules and infarctions. A small focus of chronic pleuritis was also observed. Brain and pia mater showed degeneration, necrosis and calcification with perivascular lymphoplasmacytic and granulomatous inflammation. B. melitensis was evidenced in all these organs. This systemic brucellosis is unusual in our developed countries, in human an early medical action restricts the illness to localised lesions; domestic ruminants are slaughtered at the first clinical suspicion like abortion and/or after seroconversion.

[Bacteria associated with diarrheic episodes in young camels in Niger]. / Bactéries associées à des épisodes diarrhéiques chez les chamelons au Niger.

During diarrhoeic episodes of young camels in Niger, bacteria such as Salmonella enteritidis, E. Coli, Staphylococcus sp., Clostridium perfringens and other bacteria were isolated from stool samples. Bacteria roll in this pathology is discussed, and a treatment is proposed, compared with antibiogram results.

[Differentiation of glucidolytic mycoplasmas isolated from goats by the API 50 CH system and electrophoresis]. / Différenciation par le système API 50 CH et électrophorèse des mycoplasmes glucidolytiques isolés chez la chèvre.

Carbohydrate metabolism of 62 glucidolytic strains of mycoplasma belonging to 4 species (M ovipneumoniae, M putrefaciens, M mycoides, M capricolum) has been studied using the API 50 Ch system for bacterial identification. This microtechnique and colony aspect were relevant in distinguishing M ovipneumoniae and M putrefaciens from the group M mycoides and M capricolum isolated from goats, but still presented a lack of specificity in distinguishing M mycoides from M capricolum. Similar results were obtained when the mycoplasma strains were tested by electrophoresis.

Measurement of the nonlinear refractive index of semiconductors included in monolithic étalons.

We describe a measurement technique for the determination of the nonlinear refractive index of semiconductors embedded in a Fabry-Perot cavity. This method relates the intensity-dependent spectral shift of the resonance peak to the nonlinear index variations. The use of square pulses allows the decoupling of electronic and thermal nonlinearities. Our experimental results show that this method is particularly suitable for measuring the nonlinear-optical properties of monolithic semiconductor étalons with integrated Bragg reflectors.

Isolation of Brucella melitensis biovar 3 from a chamois (Rupicapra rupicapra) in the southern French Alps.

Systemic brucellosis caused by Brucella melitensis biovar 3 was identified in a chamois (Rupicapra rupicapra) near the Parc National des Ecrins in the southern French Alps (France). Clinical signs included orchiepididymitis, polyarthritis, blindness and various neurological signs; necropsy findings included numerous calcified foci in testis, epididymis, kidney, subcutaneous connective tissue and brain. Brucella sp. were identified in brain by indirect immunofluorescence and B. melitensis biovar 3 was isolated from testis, kidney, eye, lung and joints. This report describes the first case of brucellosis and Brucella sp. isolation in chamois in France and the first case of B. melitensis isolation in this host species.

[Nasal and pulmonary flora in the goat]. / Flores nasale et pulmonaire de la chèvre.

On the basis of bacteriological examinations carried out on 75 intranasal swabs and 80 goat lung punctures, aerobic, aero-anaerobic respiratory microbes and mycoplasma were studied. Mycoplasma ovipneumoniae was isolated both from nasal flora (37%) and from the lungs (27.5%) as well as Pasteurella spp which accounted respectively for 24% and 12.5%. The nasal flora are characterised by the presence of a Gram-negative strain included in the genus Moraxella and connected with Moraxella bovis species.

[Mycoplasma bovis infection: epidemiological and clinical survey of dairy cattle farms in Morocco]. / Infection à Mycoplasma bovis: suivi épidémiologique et clinique dans des élevages bovins laitiers au Maroc.

An epidemiological survey of M bovis infection in dairy cattle was performed in 10 herds of the Gharb's region, by sampling the animals three times with a two-month interval, between November 1985 and May 1986. M bovis was isolated in six herds with calf enzootic bronchopneumonia with a total frequency of 39% during the first visit, then 25 and 13% after two and four months, respectively. The severity of the symptoms seems closely related to the age of the animals: the youngest being the most susceptible. On the other hand, M bovis was isolated in two herds from 11% of cows suffering from clinical and subclinical mastitis. The isolation occurs at any lactation stage and the infection lasted more than four months in 40% of the animals. These results suggest that mycoplasma are important bovine pathogens in Morocco.

[Aerobic and aero-anaerobic bacterial flora of the nasal cavities of lambs]. / Flore bactérienne aérobie et aéro-anaérobie des cavités nasales de l'agneau de bergerie.

On the basis of bacteriological examinations carried out on 415 intranasal swabs, aerobic and aero-anaerobic respiratory microbes were studied in lambs. A great diversity of bacteria has been found (in total 35 bacterial species and genus have been identified). This flora is characterised by the presence of gram positive cocci with a gram negative strain included in genus Moraxella and connected with Moraxella bovis species.