A novel configuration of two Brillouin amplifiers, which contains a main amplifier combined with a reshaping amplifier, is suggested to control pulse shape of Stokes pulses with steep leading edge. Dependences of puls...A novel configuration of two Brillouin amplifiers, which contains a main amplifier combined with a reshaping amplifier, is suggested to control pulse shape of Stokes pulses with steep leading edge. Dependences of pulse shapes on several param- eters are numerically simulated. By changing the distance between the two amplifiers, the leading edge of amplified pulses can be finely adjusted. Smooth and symmetrical pulses or pulses with slow leading-edge are achieved. Theoretical re- searches prove that this system is fit for shaping pulses with steep leading edge, especially, for controlling leading edge of pulses. The results provide useful and necessary theoretical basis and guidance for the future experimental research.展开更多
This paper studied spherical pulses of solutions of the system of semilinear wav e equations with the pulses focusing at a point in three space variables. It is shown that there is no nonlinear effect at leading terms...This paper studied spherical pulses of solutions of the system of semilinear wav e equations with the pulses focusing at a point in three space variables. It is shown that there is no nonlinear effect at leading terms of pulses, when the ini tial data is subcritical.展开更多
We investigate the nonlinear localized structures of optical pulses propagating in a one-dimensional photonic crystal with a quadratic nonlinearity. Using a method of multiple scales we show that the nonlinear evolut...We investigate the nonlinear localized structures of optical pulses propagating in a one-dimensional photonic crystal with a quadratic nonlinearity. Using a method of multiple scales we show that the nonlinear evolution of a wave packet, formed by the superposition of short-wavelength excitations, and long-wavelength mean fields, generated by the self-interaction of the wave packet, are governed by a set of coupled high-dimenslonal nonlinear envelope equations, which can be reduced to Davey-Stewartson equations and thus support dromionlike high-dimensional nonlinear excitations in the system.展开更多
文摘A novel configuration of two Brillouin amplifiers, which contains a main amplifier combined with a reshaping amplifier, is suggested to control pulse shape of Stokes pulses with steep leading edge. Dependences of pulse shapes on several param- eters are numerically simulated. By changing the distance between the two amplifiers, the leading edge of amplified pulses can be finely adjusted. Smooth and symmetrical pulses or pulses with slow leading-edge are achieved. Theoretical re- searches prove that this system is fit for shaping pulses with steep leading edge, especially, for controlling leading edge of pulses. The results provide useful and necessary theoretical basis and guidance for the future experimental research.
基金National Natural Science Foundation ofChina(No.10131050) Educational Min-istry of China and Shanghai Science andTehchnology Committee Foundation(No.03QMH1407)
文摘This paper studied spherical pulses of solutions of the system of semilinear wav e equations with the pulses focusing at a point in three space variables. It is shown that there is no nonlinear effect at leading terms of pulses, when the ini tial data is subcritical.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 90403008 and 10434060, and the State Key Major Research and Development Program of China
文摘We investigate the nonlinear localized structures of optical pulses propagating in a one-dimensional photonic crystal with a quadratic nonlinearity. Using a method of multiple scales we show that the nonlinear evolution of a wave packet, formed by the superposition of short-wavelength excitations, and long-wavelength mean fields, generated by the self-interaction of the wave packet, are governed by a set of coupled high-dimenslonal nonlinear envelope equations, which can be reduced to Davey-Stewartson equations and thus support dromionlike high-dimensional nonlinear excitations in the system.