Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text F. Audo, B. Kibler, J. Fatome, and C. Finot, "Observation of Peregrine-like events in focusing dispersive dam break flows," in Advanced Photonics 2018 (BGPP, IPR, NP, NOMA, Sensors, Networks, SPPCom, SOF), OSA Technical Digest (online) (Optica Publishing Group, 2018), paper NpTh2C.4. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

We propose a new approach to enhance the extinction ratio of a pulse impaired by a coherent continuous-wave background. Taking advantage of a sinusoidal phase modulation followed by a nonlinear spectral focusing and an optical bandpass filtering, we are able to significantly decrease the level of the unwanted background. The principle of the method is experimentally validated at telecommunication wavelengths.

The French Laser MegaJoule (LMJ) is a high power laser project, dedicated to fusion and plasma experiments. It will include 176 square beams involving thousands of large optical components. The wavefront performances of all those optics are critical to achieve the desired focal spot shape and limit the hot spots that could damage the components. The CEA has developed experimental methods to qualify precisely the quality of the large optical components manufactured for the project and measure the effect of various defects. For specific components (coated or parabola mirrors, lenses or gratings), classical techniques like interferometric setups may fail to measure the wavefront highest spatial frequencies (> 1 mm(-1)). In order to improve the measurements, we have proposed characterization methods based upon a laser beam diffraction interpretation. They present limits and we need to improve the wavefront measurement for high spatial frequencies (> 1 mm(-1)). We present in this paper the intermediate field measurement based upon the Talbot effect theory and the Fourier analysis of acquired intensity images. The technique consists in a double pass setup: a plane wave is transmitted through the component twice, to simplify the setup and improve the measurement. Then, intensity images are acquired at different distances with a CCD camera and lead to the wavefront power spectral density. We describe the experimental setup to measure the wavefront of large specific components. We show experimental results. Finally, we discuss about the advantages and the limits of such a method, and we compare it with our previous measurement methods.

A power-over-fiber system using a single fiber optic of 10km devoted to transmit the energy to supply a remote equipment and also the up/down-stream data exchanged between a shore station and the equipment, is presented in this paper. Firstly, we present an overview of the developed quasi-all-optical architecture and its main communication protocol: the SPI. Then, we focus on its low consumption remote equipment and more precisely on a device called “the interface instrument” which is made of two main units. One realizes the optical toelectrical conversion to provide the power supply. The other one manages the optical data. Afterwards, experimental characterizations of the prototype are given and discussed.

We describe a quasi-all-optical extension dedicated to simplifying the deployment of submarine cabled observatories. Based on power-over-fiber technologies, high power supply and data are both transmitted in one optical fiber of a few kilometers in length. We study the Raman amplification on the down-and up-stream data in the static regime with the high optical power varying from 100 mW to 4 W over a 10 km long single-mode optical fiber. We focus on the data optical budget and signal to noise ratio dependence with respect to the high optical power value and the data optical wavelength. We also present the transmission quality in the dynamic regime of this quasi-all-optical extension.

The observation and the understanding of ocean depth behaviours require the development of sea floor observatories, well equipped with real time instrumentation. However, a large-scale deployment of such a network is expensive and needs a complex infrastructure with power supply and data exchange issues. The main objective of this study is to develop a flexible and low cost extension for existing observatory networks. The proposed and investigated solution is a quasi-alloptical extension, which consists in deploying a fibre optic devoted to transport both the energy required to supply the instrument and the up/down-stream transmitted data. In this paper, we present the architecture of this quasi-all-optical extension and we discuss about its feasibility thanks to experimental results.

Light detection and ranging (LIDAR) is currently used for bathymetric measurement or underwater target detection. A new underwater-target detection scheme named modulated lidar was recently proposed. The study reported here deals with optimization of the modulation process to be applied under such detection conditions. A theoretical model was extracted from available experimental results by deconvolution and further used to simulate realistic backscattered signals for the development of a new modulation scheme. Then, an optimum set of amplitude modulation code parameters was obtained by maximizing the target signal-to-noise ratio. This paper will highlight some particularly promising waveform configurations.