High-sensitive Optical Pulse-Shape Characterization using a Beating-Contrast-Measurement Technique

Ultrahigh-speed optical transmission technology, such as optical time domain multiplexing or optical signal processing is a key point for increasing the communication capacity. The system performances are strongly related to pulse properties. We present an original method dedicated to short pulse-shape characterization with high repetition rate using standard optical telecommunications equipments. Its principle is based on temporal measurement of the contrast produced by the beating of two delayed optical pulses in a highbandwidth photodetector. This technique returns firstly reliable informations on the pulse-shape, such as pulsewidth, shape and pedestal. Simulation and experimental results evaluate the high-sensitivity and the high-resolution of the technique allowing the measurement of pulse extinction ratio up to 20 dB with typical timing resolution of about 100 fs. The compatibility of the technique with high repetition rate pulse measurement offers an efficient tool for short pulse analysis

Investigation of SOA-based wavelength conversion at 80 Gb/s using bandpass filtering

This paper presents a simple and effective 80 Gb/s wavelength conversion scheme by using Cross Gain Modulation in a Semiconductor Optical Amplifiers (SOA) in conjunction with filtering the blue shifted component of the probe spectrum to give a non-inverted output signal

Electrons surfing on a sound wave as a platform for quantum optics with flying electrons

Electrons in a metal are indistinguishable particles that strongly interact with other electrons and their environment. Isolating and detecting a single flying electron after propagation to perform quantum optics like experiments at the single electron level is therefore a challenging task. Up to date, only few experiments have been performed in a high mobility two-dimensional electron gas where the electron propagates almost ballistically. Flying electrons were detected via the current generated by an ensemble of electrons and electron correlations were encrypted in the current noise. Here we demonstrate the experimental realisation of high efficiency single electron source and single electron detector for a quantum medium where a single electron is propagating isolated from the other electrons through a one-dimensional channel. The moving potential is excited by a surface acoustic wave, which carries the single electron along the 1D-channel at a speed of 3\mum/ns. When such a quantum channel is placed between two quantum dots, a single electron can be transported from one quantum dot to the other, which is several micrometres apart, with a quantum efficiency of emission and detection of 96% and 92%, respectively. Furthermore, the transfer of the electron can be triggered on a timescale shorter than the coherence time T2* of GaAs spin qubits6. Our work opens new avenues to study the teleportation of a single electron spin and the distant interaction between spatially separated qubits in a condensed matter system.Comment: Total 25 pages. 12 pages main text, 4 figures, 5 pages supplementary materia

Transmission de données et laser à cascade quantique

National audienceToday, optical fibres are high-technology carriers of information, forming a world-wide network. Tomorrow, free space optical communication systems could be an attractive solution by use of chaos-based secure.Aujourd'hui transmises de manière confinée, en partie dans la fibre optique, nos données pourraient se propager dans l'atmosphère grâce au laser à cascade quantique. Il s'agit d'une innovation qui intéresse d'abord les militaires, notamment pour sa capacité de cryptage

Performance en boucle à recirculation à 10 Gbit/s d'un régénérateur 3R tout-optique à base d'amplificateurs optiques à semi-conducteurs et insensible à la polarisation

session 4 « Systèmes de transmission haut débit » [Ve4.3]National audienceDans cet article, nous présentons les résultats obtenus lors d'une étude en boucle à recirculation d'un régénérateur optique 3R possédant une architecture originale à base d'amplificateurs optiques à semi-conducteurs (SOA) et présentant une faible sensibilité à la polarisation. Ce dispositif a permis de réaliser une transmission de 100000 km (1000 cascades de régénérateur) sans erreur

Etude numérique et expérimentale de l'évolution du taux d'erreurs binaires au passage dans un régénérateur optique

session « affiches II » [B24], http://www.comelec.enst.fr/jnog2004/papers/B24_Bramerie.pdfNational audienceL'évolution du taux d'erreurs binaires (TEB) après N passages dans un régénérateur optique 3R est étudié dans ce papier. Il est montré expérimentalement à 10 Gbit/s que le TEB évolue linéairement en fonction du nombre de passages dans le régénérateur. Nous avons également mis en évidence que le facteur Q ne permet plus d'évaluer le TEB après plusieurs passages dans un régénérateur

Identification of a t(3;4)(p1.3;q1.5) translocation breakpoint in pigs using somatic cell hybrid mapping and high-resolution mate-pair sequencing

<div><p>Reciprocal translocations are the most frequently occurring constitutional structural rearrangements in mammalian genomes. In phenotypically normal pigs, an incidence of 1/200 is estimated for such rearrangements. Even if constitutional translocations do not necessarily induce defects and diseases, they are responsible for significant economic losses in domestic animals due to reproduction failures. Over the last 30 years, advances in molecular and cytogenetic technologies have led to major improvements in the resolution of the characterization of translocation events. Characterization of translocation breakpoints helps to decipher the mechanisms that lead to such rearrangements and the functions of the genes that are involved in the translocation. Here, we describe the fine characterization of a reciprocal translocation t(3;4) (p1.3;q1.5) detected in a pig line. The breakpoint was identified at the base-pair level using a positional cloning and chromosome walking strategy in somatic cell hybrids that were generated from an animal that carries this translocation. We show that this translocation occurs within the <i>ADAMTSL4</i> gene and results in a loss of expression in homozygous carriers. In addition, by taking this translocation as a model, we used a whole-genome next-generation mate-pair sequencing approach on pooled individuals to evaluate this strategy for high-throughput screening of structural rearrangements.</p></div

Fluorescent in situ hybridization of the pIRS-PCR probe, derived from hybrid Hb1.8, on normal pig metaphase chromosomes.

<p>pIRS-PCR products label the entire length of chromosomes 1, 8, 10, 16, X, and partially chromosomes 3, 4 and 5. Chromosomes 3 and 4 are indicated with yellow and blue arrows respectively (a), and are magnified in (b). On these two chromosomes, signals are observed on the p arm for SSC3 and in the p15-q22 region for SSC4, confirming the presence of the translocated derivative chromosome der(4) in Hb1.8 hybrid clone.</p