Graphene Based Photonic Crystal Slow Light Waveguide

The optical buffer is the key device in all light commications.To satisfy the increasing demand of optical buffer,we propose three kinds of Graphene-based photonic crystal slow light waveguide,and be used to the optical buffer,we decide to design the effective index varing periodically photonic crystal slow light waveguide and use a plane wave expansion to calculate the dispersion curves.Firstly,we propose a PC with 450-rotated square lattice to form the line-defect waveguide,of which,ng=(137.2±4),bandwidth = 2.31%,and the NDBP = 3.17 can be achieved.Besides,when the voltage applied to the graphene is varied,the slow light performance including center frequency,the group index and bandwidth can be changed dynamically.Secondly,we propose graphene-based photonic crystal coupled cavity waveguide.In the 600 photonic crystal coupled cavity waveguide,when the frequency varies from 29.62 THz to 30.02 THz,ngremains to be(177.5±10),the NDBP can reach up to 2.38.Next,we present the 900 photonic crystal coupled cavity waveguide,when the frequency varies from 28.7 THz to 29.5THz,ng remains to be(142.5 ±7.9),the NDBP is as high as 3.92,which improved the slow light performance.Finally,we describe some measure of optical buffer performance parameters,mainly include cache time,cache size and bit length.We apply the three kinds of waveguide with better performance to the cache,by theoretical calculation,the maximum buffer capacity using 900 photonic crystal coupled cavity waveguide can be achieved as 331.6bit,and the maximum delay time is 475.00ps,and the maximum bit length of buffer 3.0um.