Instabilidade modulacional em equações não lineares de Schrödinger

• Ano de defesa: 2015
• Autor(a) principal: Alves , Erivelton de Oliveira
• Orientador(a): Avelar , Ardiley Torres
• Banca de defesa: Avelar , Ardiley Torres, Cardoso , Wesley Bueno, Souza , Márcio Adriano Rodrigues, Bazeia Filho , Dionízio, Malbouisson , Jorge Mario Carvalho
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Fisica (IF)
• Departamento: Instituto de Física - IF (RG)
• País: Brasil
• Palavras-chave em Português: Sólitons; Instabilidade modulacional; Não linearidade
• Palavras-chave em Inglês: Solitons; Mmodulational stability; Nonlinearity
• Área do conhecimento CNPq: FISICA DAS PARTICULAS ELEMENTARES E CAMPOS::TEORIA GERAL DE PARTICULAS E CAMPOS
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/6750

In this work the influence of a saturable nonlinearity on the modulation instability (MI) in the contexts oppositely directed coupler and optical fibers in the presence of high-order effects are investigated. The instability gain is attained by using standard linear stability analysis. In particular, we study the combination of a saturable nonlinearity with self-steepening or intrapulse Raman scattering effects on MI for both normal and anomalous group velocity dispersion regimes. In the case of the directional couplers we investigated how the gain of modulational instability is affected by the saturation model and self-steepening or intrapulse Raman scattering effects. Our results show that instability gain exhibits significant changes due to the effects of saturable nonlinearity. When we analyze self-steepening effect, we show that its effective influence on the gain of the modulational instability depends on the algebraic sum of the parameters in each channel. Analyzing the intrapulse Raman scattering, we observe a symmetry break in the gain regions when the Raman scattering parameter with opposite signals in each channel is considered. Finally, in the context of optical fibers we show how the reduction of the Of the gain frequency of the IM, induced by saturation, can drastically limit the formation of soliton trains.