Search results for "PROPAGATION"
showing 10 items of 676 documents
Microwave experiments on electromagnetic evanescent waves and tunneling effect
1993
A set of experiments is described to measure the decay of electromagnetic evanescent waves and the tunneling effect through an airgap. The experiments are performed using microwaves and have been designed to be carried out by third year students of physics. The proposed experimental setup can be regarded as a quantum mechanical simulator for the one‐dimensional motion of a particle.
Kinetic Interaction of Cold and Hot Protons With an Oblique EMIC Wave Near the Dayside Reconnecting Magnetopause
2021
STR acknowledges support from the ISSI international team Cold plasma of ionospheric origin in the Earth's magnetosphere and of the Ministry of Economy and Competitiveness (MINECO) of Spain (grant FIS2017-90102-R). Research at IRAP was supported by CNRS, CNES and the University of Toulouse. JHL and DLT acknowledge support from NASA Grant 80NSSC18K1378. RED was supported by NASA grants 80NSSC19K070 and 80NSSC19K0254. MA was supported by SNSA Grant 56/18. SKV and RCA acknowledge support from NASA Grant 80NSSC19K0270. Work performed by MMS team members is supported by NASA contract NNG04EB99C.
Regenerative 40 Gbit/s wavelength converter based on similariton generation.
2005
International audience; We present an all-optical regeneration technique based on spectral filtering of self-similar parabolic pulses (similaritons). In particular, we demonstrate numerically and experimentally that ghost pulses, which occur in the zero bit slots of telecommunication pulse trains, can be effectively suppressed. These results are obtained with a 40 Gbit/s pulse train.
Modulational instability in optical fibers with arbitrary higher-order dispersion and delayed Raman response
2006
International audience; We analyse modulational instability (MI) of electromagnetic waves in a large variety of optical fibers having different refractive-index profiles. For the normal-, anomalous-, and zero-dispersion regimes of the wave propagation, we show that whenever the second-order dispersion competes with higher-order dispersion (HOD), propagation of plane waves leads to a rich variety of dynamical behaviors. Most of the richness comes from the existence of critical behaviors, which include situations in which the HOD suppresses MI in the anomalous dispersion regime, and other situations in which the HOD acts in the opposite way by inducing non-conventional MI processes in the nor…
Spatiotemporal pulse shaping with multimode nonlinear guided waves
2018
We experimentally and theoretically investigate complex temporal pulse reshaping that accompanies Kerr beam self-cleaning in multimode optical fibers. We also study the output beam shape dependence on initial conditions.
All-Normal Dispersion Photonic-Crystal Fiber for Pulse-Preserving Supercontinuum Generation near 800 nm
2013
All-normal dispersion photonic-crystal fiber is designed for pulse-preserving supercontinuum generation near 800 nm. Supercontinuum generation is analyzed numerically addressing the role of pump pulse energy and offset of the pump wavelength from the zero point of 3d-order dispersion.
Shallow water rogue wavetrains in nonlinear optical fibers
2013
International audience; In addition to deep-water rogue waves which develop from the modulation instability of an optical CW, wave propagation in optical fibers may also produce shallow water rogue waves. These extreme wave events are generated in the modulationally stable normal dispersion regime. A suitable phase or frequency modulation of a CW laser leads to chirp-free and flat-top pulses or flaticons which exhibit a stable self-similar evolution. Upon collision, flaticons at different carrier frequencies, which may also occur in wavelength division multiplexed transmission systems, merge into a single, high-intensity, temporally and spatially localized rogue pulse.
Wave Propagation in a 3-D Optical Waveguide
2003
In this paper we study the problem of wave propagation in a 3-D optical fiber. The goal is to obtain a solution for the time-harmonic field caused by a source in a cylindrically symmetric waveguide. The geometry of the problem, corresponding to an open waveguide, makes the problem challenging. To solve it, we construct a transform theory which is a nontrivial generalization of a method for solving a 2-D version of this problem given by Magnanini and Santosa.\cite{MS} The extension to 3-D is made complicated by the fact that the resulting eigenvalue problem defining the transform kernel is singular both at the origin and at infinity. The singularities require the investigation of the behavio…
Measured and predicted light attenuation in dense coastal upslope fog at 650, 850, and <inline-formula><math display="inline" overflow="scro…
2008
Free-space optics FSO has gained considerable importance in this decade of demand for high-bandwidth transmission capabilities. FSO can provide the last mile solution, but the availability and reliability issues concerned with it have received increasing attention and need thorough investigation. In this work, we present our results on fog attenu- ation measurement and prediction at wavelengths 650, 850, and 950 nm with peak values up to 500 dB/km. For the attenuation measurement, optical wavelengths are transmitted over the same path of fog in free air to a receiver, measuring the power at every wavelength. The measure- ment of fog attenuation was performed at the France Telecom RD free-sp…
Designing Precoding and Receive Matrices for Interference Alignment in MIMO Interference Channels
2017
Interference is a key bottleneck in wireless communication systems. Interference alignment is a management technique that align interference from other transmitters in the least possibly dimension subspace at each receiver and provides the remaining dimensions for free interference signal. An uncoordinated interference is an example of interference which cannot be aligned coordinately with interference from coordinated part; consequently, the performance of interference alignment approaches are degraded. In this paper, we propose a rank minimization method to enhance the performance of interference alignment in the presence of uncoordinated interference sources. Firstly, to obtain higher mu…