The Study And Numerical Investigation On Slow Solitons In The Bragg Gratings With A Hyperbolic Tangent Apodization

With the rapid development of the human-society, the demand of the information need the communication network which with high-capacity and high-speed. The development of all-optical communication network makes this to be possible. So in recent years, there has been a lot of interest on optical buffer and slow light because these technologies are the basis for optical switching communication network. Fiber Grating Soliton Buffer is a new means of it. Based on the nonlinear coupled-mode theory, the Bragg Grating (BG) solitons and the Fiber solitons which are the solution for the non-linear coupled mode equations (NLCME's) were discussed in this paper. We use optical fiber soliton but BG soliton as input pulse in our discussion, which is much more approximate to light source for the practical purpose, so the effects of the soliton's energy and formation with other initiate parameters were analyzed. The characteristics of the motion of fiber solitons transmitted through the Fiber Bragg Grating were simulated by MATLAB, then this results were repaired with the phenomenon which we get by experiment. Based on this study, we numerically and analytically investigate the formation and propagation motion of optical soliton in the Bragg grating which with hyperbolic tangent apodization in the middle section in order to get slower solitons. The result show that the apodization step has the greatest impact on the soliton's velocity in the three parameters which we simulated. Thus, in the progress of a grating manufacture, we can select the kind of fiber with larger nonlinear coefficient and appropriate apodization profile. While in the optical buffer system, the soliton's velocity can be controlled by changing s (changing the wavelength of the input pulse or the Bragg wavelength of FBG). Therefore, the velocity of the solitons can be tunable by changing the frequency detuning on a small scale.