Search results for "Linear"
showing 10 items of 7165 documents
A comment on “Research on the nonlinear pulse propagation by numerical analysis” by Li and Yin [Optik 12 (13) (2011) 1195–1200]
2012
In the article entitled "Research on the nonlinear pulse propagation by numerical analysis" , Li Li and Aihan Yin summarize the key elements affecting the nonlinear propagation of an optical pulse in an optical fiber. We comment these results.
The cancellation of nonlinear and dispersive phase components on the fundamental optical fiber soliton: a pedagogical note
2001
We consider the separate effects of nonlinear and dispersive propagation on a hyperbolic secant pulse propagating in an optical fiber. In particular, for small propagation distances, we present a straightforward derivation of the time-varying phase components developed across the pulse due to self-phase modulation (SPM) and group velocity dispersion (GVD). In this limit, we show that GVD is associated with a nonparabolic temporal phase which can exactly cancel the nonlinear phase component due to SPM across the entire pulse profile. The cancellation condition gives the launch condition for a fundamental optical fiber soliton.
Non-existence of dark solitons in a nonlinear Schrödinger-Maxwell-Bloch fibre system
2000
We consider the coupled system of nonlinear Schrodinger and Maxwell-Bloch (NLS-MB) equations, which govern the nonlinear pulse propagation in erbium doped optical fibres. With the help of the Painleve singularity structure analysis, we prove the non-existence of optical solitons in the NLS-MB fibre system in the normal dispersion regime.
Generation and detection of optical rogue-wave-like fluctuations in fiber Raman amplifiers
2009
Rogue wave-like statistics is reported in a fiber Raman amplifier. The pump-signal noise transfer leads to the development of large peak-power fluctuations following a powerlaw probability distribution. Discrimination of the rarest events is demonstrated.
Polychromatic Cherenkov radiation and supercontinuum in tapered optical fibers
2012
We numerically demonstrate that bright solitons in tapered optical fibers can emit polychromatic Cherenkov radiation providing they remain spectrally close to the zero dispersion wavelength during propagation along the fiber. The prime role in this phenomenon is played by the soliton self-frequency shift driving efficiency of the radiation and tuning of its frequency. Depending on tapering and input pulse power, the radiation is emitted either as a train of pulses at different frequencies or as a single temporally broad and strongly chirped pulse.
Radiating and non-radiating trains of light pulses in dispersion-managed optical fiber systems
2005
We show theoretically that the radiation picture of small trains of closely packed light pulses with Gaussian input profile, exhibits both some similar features and some fundamental differences when compared to the radiating behavior of a solitary pulse in a dispersion-managed optical fiber system. For small map strengths, the pulse trains strongly radiate away energy, and there, the total amount of radiated energy increases linearly as a function of the length of the pulse train. For large map strengths, the amount of radiated energy increases rather smoothly as a function of the length of the pulse train. We establish the existence of a map strength region, in which light pulses with init…
Surface Reconstruction of Transparent Objects by Polarization Imaging
2008
This paper focuses a method to acquire the surface of transparent objects for 3D measurement. The technique relies on the so called ?Shape from Polarization? technique. The principle of this polarization imaging technique is as follows: after being reflected, an unpolarized light becomes partially linearly polarized. The surface normals can be evaluated by analyzing their polarization parameters and by knowing the refractive index of the object to be controlled. Finally, the 3D shape is obtained by integrating the normals field. After an introduction to expose the problematic, section 2 exposes the principles of polarization technique. The third and the last section deal with the polarimetr…
Cavity solitons in bidirectional lasers.
2007
We show theoretically that a broad area bidirectional laser with slightly different cavity losses for the two counterpropagating fields sustains cavity solitons (CSs). These structures are complementary, i.e., there is a bright (dark) CS in the field with more (less) losses. Interestingly, the CSs can be written/erased by injecting suitable pulses in any of the two counterpropagating fields.
Experimental investigations of backward transition radiation characteristics in extreme ultraviolet region
2011
ABSTRACT This report summarizes the results of an experiment dedicated to the observation of backward transition radia-tion in the EUV spectral region. This radiation was ge nerated by an 855MeV electron beam at a molybdenumtarget. The radiation characteristics in the EUV region are compared to those in the optical region. It wasshown that the radiation measured in the EUV region was more intense than theoretically predicted. As aresult the EUV radiation yield seems to be suci ent for standard beam prole diagnostics.Keywords: EUV, Transition radiation, Beam diagnostics 1. INTRODUCTION Transverse prole diagnostics in mo dern electron linear accelerators as F ELs or injector linacs is mainl…
Photorefractive amplifier-converter and coherent oscillator with nonexponential gain
2001
For some parametric interactions with identically zero exponential gain for the signal wave the intensity of the idler wave can grow as a second power of the propagation coordinate. Such an amplification is revealed for the parametric mixing of four copropagating waves in BaTiO3; two of them are ordinarily polarized and the two others are extraordinarily polarized. This mixing is used to build up a coherent oscillator. A reasonable qualitative agreement of the experimental results with the calculated data is demonstrated.