Research On The Ultrafast Optical Switching Of Pulse Trapping In Photonic Crystal Fibers

Ultrafast all-optical switching is an important technique in future ultrahigh speed optical communication systems. Photonic crystal fibers (PCFs) have recently attracted significant attention because of their specifically controlled dispersion properties and their great potential applications in the fields of optical telecommunication,Therefore, the optical properties of a PCF differ remarkably from those of standard fibers. Ultrafast all optical switching by use of pulse trapping has high repetition frequency, high trapping efficiency and controlled dispersion properties The properties of ultrafast all optical switching by use of pulse trapping are analyzed. The main research results are listed below:Firstly, the propagation of pulse trapping in PCFs is limited by many physical factors, and the theoretical analysis is very complicated, so numerical simulation becomes crucial research methods. Based on the physical model of optical pulses propagation in PCFs, we have independently developed the computer program which can simulate the process of linear and nonlinear propagation of optical pulses. Compared with the experimental and theoretical results reported in literatures, the validity of the computation results of our program is confirmed.Secondly, an generic expression for pulse trapping which includes the influence of higher-order effects such as higher-order dispersion (HOD), self-steepening (SS), stimulated Raman scattering (SRS) etc. The numerical results show different phenomena are observed depending on whether the wavelength of the signal pulse is located in the normal or the anomalous dispersion region. In particular, it is found that the phenomenon of pulse trapping occurs when the signal wavelength is located in the normal dispersion region while the pump wavelength is located in the anomalous dispersion region, the pump pulse is red-shifted ,the trapped pulse is blue-shifted. This phenomenon is not observed when the effect of Raman scattering is not active.Thirdly, the characteristics of ultra-fast all optical switching by use of pulse trapping are analyzed. Numerical simulations show as the input peak power of the pump pulse is increased, the red-shift of the Raman soliton is considerably enhanced with the simultaneous further blue-shift if the trapped pulse to satisfy the condition of group velocity matching. It is interesting to note that although the other pulses are also overlapped with the soliton pulse, they are not trapped. The trapping efficiency...