Theoretical Study Of Micro-nano Optical Pulse Compressor

As the development of device design theory and fabrication techniques in recentyears, miniaturization of electronic and photonic devices is becoming the inexorabletrend. It makes the micro/nano structure photonic devices possible with the successpreparation of low-loss micro-nano optical fiber. The micro-nano fiber which isrationally designed with high nonlinear coefficient and its dispersion is thousandtimes larger than conventional fiber. These characteristics provide a possible way tostudy efficient micro/nano optical pulse compressor. In this article, we mainlyproposed the usage of micro/nano fiber to realize all optical pulse compression. Thecharacteristics of the micro/nano fiber pulse compressor are theoretically studiedthrough numerical simulation. We believe that the work will lay the foundation for therealization of micro-nano-scale all optical pulse compression and the future exploringthe application of micro-nano fiber in some extent. The main research contents arelisted as follows:First, based on the fiber model theory, the transmission characteristics have beentheoretically studied. Based on numerical simulations of a2-layer-structuredcylindrical waveguide, Maxwell equations and boundary conditions, we study thepropagation properties of the micro/nano fiber. These mainly contain the mode fielddistribution, propagation constant, single-mode condition, nonlinear parameter,waveguide dispersion, transmission efficiency and other important parameters.Second, in order to illustrate the influence of higher-order nonlinear effect onmicro/nanowire pulse compressor, we added intrapulse stimulated Raman scattering,third-order dispersion and self-steepening effect on pulse compression in themicro/nano optical fiber. The results of simulation show that among the three higherorder nonlinear effects, the intrapulse stimulated Raman scattering almost have noinfluence on the pulse compression, and the third-order dispersion has little effect onthe pulse compression, even when the soliton order is small the influence is almostnegligible, while the effect of self-steepening on pulse compression is slightly largerthan the effect of stimulated Raman scattering and third-order dispersion.Finally, based on silicon nanowire, we have discussed the influences of differentcore diameters on pulse compression features with two kinds of different pulsecompression methods. It is very difficult to realize high accuracy preparation of micro/nano fiber in currently drawing conditions, so the size of core diameter alwaysfluctuates in a small range. Based on the characteristics that the silicon nanowire canrealize soliton effect pulse compression in its region of abnormal group velocitydispersion (GVD) and can achieve negative chirped pulse compression in its region ofnormal GVD. We have discussed the influences of different core diameters on pulsecompression features in these two kinds of different pulse compression methods. Thestudy contents of pulse compression features include compression factor, qualityfactor and the optimum fiber length. When we compress pulse with soliton-effect,there is almost no influence on pulse compression characteristics when the corediameter increases5%on the basis of350nm. But there is significant influence on thestability of pulse compressor characteristics when the core diameter decreases3%.For the negative chirp pulse compression, the compression factor increases with theincrease of the diameter until the core diameter larger than300nm, the quality factorand the optimum fiber length inversely proportional to the compression factor.