Theoretical Study Of Micro/Nano Hollow Optical Fiber Pulse Compressor

With the improvement of the design theory and rapid development of fabrication techniques for optoelectronic device, miniaturization has become the important trends. It is possible to make the micro/nano structure photonic devices with the low-loss micro/nano fiber, which has been prepared successfully. For the micro/nano fibers, they have large waveguide dispersion, which is favored for pulse compression. In this thesis, we have proposed the all optical pulse compressor based on micro/nano hollow core fiber. The characteristics of the micro/nano hollow core fiber pulse compressor have been theoretically studied by numerical simulation. We believe that the work will lay the foundation for the realization of micro-nano-scale all optical pulse compression and the future application of micro-nano fiber in some extent. The main research contents are listed as follows:1. Based on the waveguide theory, the linear and nonlinear propagation characteristics have been studied, including the modal field distribution, energy flux distribution, waveguide dispersion and nonlinear coefficient for silica and silicon micro/nano hollow fiber by numerical simulation. The propagation properties can be regulated and controlled by changing the fiber structure. The results show that micro/nano fiber have large evanescent field and the energy confining ability of silicon micro/nano hollow fiber is better than silica. With the hollow core size decreases, local field enhancement phenomenon appears for the micro/nano hollow core fiber. Moreover, varying the hollow core size provides a freedom for adjusting the modal field and dispersion and nonlinearity. The waveguide dispersion and nonlinear coefficient for silicon micro/nano hollow fiber is larger than silica one.2. Based on soliton effect pulse compression method, the influences of fiber structure and input laser parameters have been discussed for the micro/nano pulse compressor. The result indicates that adjusting the fiber diameter reasonably, the best pulse compression effect can be got. The micro/nano hollow core fiber can compress the optical pulse efficiently than the solid-core fiber. And by regulating the size of the hollow core can effectively control the ability of the pulse compression. The large initial chirp will reduce the quality of pulse compression, and the high energy input pulse makes better compression.