Propagation Characteristics Of Silicon-based Micro-nano Optical Fiber

Inspired by the requirements of ultra-high speed and ultra-large capacity communication system,the performance and integration requirements of optoelectronic system are constantly improved,and the miniaturization and functionalization of optoelectronic devices have become an important development trend.Among the numerous micro/nano waveguides,micro/nano fiber has become one of the hot spots in the field of micro-nano photonics due to its excellent properties such as small size,strong optical field confinement ability,low loss and easy integration.In addition,silicon-based optoelectronic devices can provide more possibilities for optoelectronic devices by virtue of mature silicon-based processing technology,cheap material cost and its good hybrid integration characteristics.Based on the application requirements of functional micro/nano optoelectronic devices,the propagation characteristics of silicon-based micro/nano optical fiber are numerically studied in this thesis.It is found that the waveguide has unique mode and dispersion characteristics,and we can tune the modal field and dispersion based on structural design and the applied bias.The main contents of this thesis are as follows:(1)The mode field and dispersion characteristics of silicon-based micro/nano fiber have been numerically studied,and the influence and variation rules of waveguide parameters on its propagation characteristics have been obtained.The theoretical model of silicon nanowire waveguide is established and the transmission characteristics of different silicon-based micro/nano fibers are numerically simulated.Numerical results show that the structure has strong optical field confinement ability and can achieve large and tunable anomalous dispersion in a wide spectral range.(2)The propagation characteristics of silicon-based hybrid waveguides have been numerically studied,and the influence of waveguide parameters and applied electric field on the propagation characteristics has been obtained.The theoretical model of single crystal silicon micro/nano fiber coated with lithium niobate is established,and the mode field characteristics of the waveguide are numerically simulated.By changing the structure and applied electric field of micro/nano fiber,the effect of waveguide geometry and applied electric field on the dispersion of the hybrid micro-nano fiber waveguide is verified.