Studies On Transmission Of Femtosecond Optical Solitary Waves In Optical Fibers

We investigate the transmission of femtosecond pulses in an optical fiber. The influence of optical source chirp on femtosecond soliton interaction is studied numerically, and the unequal amplitude method can reduce the interaction. In addition high-order coupled equations governing the evolution of two orthogonal polarization components of the same wave are derived by using multi-dimension derivation expansion method of singular perturbation theory and the dispersion relation. Furthermore, a class of optical solitary wave solutions, such as the bright-bright, dark-dark, bright-dark, and combined solitary waves are found under certain parametric conditions. The properties of these optical solitary solutions are presented. Finally, we investigate the stability of theses solitary waves. What we discussed in this paper may be helpful to achieve the distorted transmission of femtosecond pulses in optical fibers experimentally. The main results are as follows:1) The influence of optical source chirp on femtosecond soliton interaction is studied numerically.Results show that femtosecond soliton interaction with chirp from optical source is more serious than that without optical source chirp. The former can cause larger error code rate in soliton communication systems. The results also show unequal amplitude method can reduce the interaction between femtosecond soliton in the presence of optical source chirp in a certain degree.2) Based on the Maxwell equations of nonlinear media, high-order coupled equations governing the evolution of two orthogonal polarization components of the same wave are derived by using multi-dimension derivation expansion method of singular perturbation theory, and the suitable application range is presented.3) Coupled higher-order nonlinear Schr(?)dinger equations (CHNLSE), governing the evolution oftwo orthogonal polarization components of ultrashort optical pulse in birefringent fiber, are derived from the dispersion relation.4) In addition, a class of optical solitary wave solutions, such as the bright-bright, dark-dark, bright-dark, and combined solitary waves, especially the interesting W-shaped solitary wave solutions for CHNLS equations are found under certain parametric conditions. The properties of these optical solitary solutions are presented. Furthermore, we investigate the stability of theses solitary waves under some initial perturbations by employing numerical simulation methods.