Search results for "and losses"
showing 4 items of 4 documents
Discrete spectral incoherent solitons in nonlinear media with noninstantaneous response
2011
International audience; We show theoretically that nonlinear optical media characterized by a finite response time may support the existence of discrete spectral incoherent solitons. The structure of the soliton consists of three incoherent spectral bands that propagate in frequency space toward the low-frequency components in a discrete fashion and with a constant velocity. Discrete spectral incoherent solitons do not exhibit a confinement in the space-time domain, but exclusively in the frequency domain. The kinetic theory describes in detail all the essential properties of discrete spectral incoherent solitons: A quantitative agreement has been obtained between simulations of the kinetic…
Modulational instability in resonant optical fiber with higher-order dispersion effect
2010
International audience; The modulational instability (MI) of an electromagnetic wave in a resonant optical fiber with a two-level system is investigated. In the normal dispersion regime, we find the occurrence of nonconventional MI sidebands which are induced by the two-level resonant atoms. We also observe that the MI gain spectra are suppressed by the higher-order dispersion effect in the anomalous dispersion regime.
Condensation and thermalization of classsical optical waves in a waveguide
2011
http://pra.aps.org/; International audience; We consider the long-term evolution of a random nonlinear wave that propagates in a multimode optical waveguide. The optical wave exhibits a thermalization process characterized by an irreversible evolution toward an equilibrium state. The tails of the equilibrium distribution satisfy the property of energy equipartition among the modes of the waveguide. As a consequence of this thermalization, the optical field undergoes a process of classical wave condensation, which is characterized by a macroscopic occupation of the fundamental mode of the waveguide. Considering the nonlinear Schrödinger equation with a confining potential, we formulate a wav…
A Cross-Cultural Exploratory Study of Health Behaviors and Wellbeing During COVID-19
2021
This study explored the influence of the COVID-19 pandemic on perceived health behaviors; physical activity, sleep, and diet behaviors, alongside associations with wellbeing. Participants were 1,140 individuals residing in the United Kingdom (n = 230), South Korea (n = 204), Finland (n = 171), Philippines (n = 132), Latin America (n = 124), Spain (n = 112), North America (n = 87), and Italy (n = 80). They completed an online survey reporting possible changes in the targeted behaviors as well as perceived changes in their physical and mental health. Multivariate analyses of covariance (MANCOVA) on the final sample (n = 1,131) revealed significant mean differences regarding perceived physical…