Research On Broadband Low Dispersion Characteristics Of Photonic Crystal Waveguides Based On Material Adjustment

The development of information and communication technologies prompted people to look more toward Optical Networks.However,the current Optical Network remain plenty of Photoelectric Conversion,which strongly limit the speed of network.Optical switch and optical memory which are based on optical buffer technique are key devices in all-optical networks.Photonic crystal are receiving more and more interest for realization of optical buffer.It has apparent advantage on small size,wide bandwidth,easy integration,room-temperature running.And the investigation on photonic crystal slow light has achieved many results.Almost all of the researches focus on reducing group velocity dispersion while reducing speed of light signal,and at the same time,adequate bandwidth must be guaranteed.In real world applications,photonic crystal optical devices must have the function of reconfigurable and switchable.It has important significance to study slow light performance optimization and dynamic adjustable.In this thesis,we mainly studied structure and slow light performance of two-dimensional photonic crystal waveguide.Our research ideas are combining material schemes and structure optimizing methodology to improve slow light properties.At first,we reviewed the general principle and concept of photonic crystal and slow light performance,we gave a brief introduction to theoretical research techniques and popular simulation tools on photonic crystal.We took Plane Wave Expansion approach to calculate the band structure in this paper.Then,we designed two types of photonic crystal with hexagon ring scatterers and circular scatterers.We selected one sort of structure variable and material variable respectively to study their effect on bandgap properties.After that,we introduced defect to the novel kind of photonic crystal with hexagon ring scatterer to form a new slow light waveguide.By gradually adjusting refractive index of optofluidic,internal radius of hexagon ring,internal radius of optofluidic and translation distance of the first row,we finally obtained optimized result on slow light performance that bandwidth reach up to 92.9nm and GVD lower than 7.82 pm2/mm with ng equal to15.66.The result is superior to published papers.At last,we studied a typical W1 photonic crystal waveguide with circular air hole scatterers.We discussed the change regulation of slow light performance when tuning the first and second row holes reflective index n1 and n2,then we add radius of the first row holes r1 as a new variation.By properly adjusting various combinations of n1 and r1,we finally obtained NDBP higher than 0.32 at a wide group index range from 30 to 200.The research has shown the feasibility of post-fabrication technology to generate high performance slow light.Finally we stated and summarized all the work we've done in this thesis,and figured out prospects for future research.