光子晶体耦合腔波导低色散慢光的研究

Study on the Slow Light Characteristics of Low-Dispersion Photonic Crystal Coupled-Cavity Waveguide

设计一种由4孔微腔组成的二维三角晶格光子晶体耦合腔波导,应用时域有限差分法(FDTD)模拟计算TE偏振光的透射谱,获得波长在1.55941μm处最大群折射率ng=1460.31、群速度vg=c/1460.31的慢光.该光子晶体耦合腔波导传输光的群折射率随波长(ng-λ)变化关系呈现"U"型结构,在"U"型底部出现中心波长1.55917μm、平均群折射率～ng=721.92、带宽Δλ=0.35nm、平坦率σ=0.02%的低色散慢光。进一步研究表明,移动耦合腔波导第一排空气柱的位置不仅可以在"U"型底部区域产生中心波长1.60412μm、带宽Δλ=6.67nm、平均群折射率ng=41.05的低色散慢光,而且可以在波长1.56177μm处获得最大群折射率ng=2173.12、群速度vg=c/2173.12的慢光.

We designed a two-dimensional triangular lattice photonic crystal coupled-cavity waveguide of four hole micro cavities. Transmission Spectra of TE-polarized light are calculated by using the finite-difference time- domain （FDTD） method and slow light with a maximum group ng = 1460.31 index, maximum group velocity vg = c/1460.31 at wavelength 1. 55941/xm are obtained. This photonic crystal coupled-cavity waveguide can produce ＂U＂ type group index-frequency curves with low dispersion slow light area at the bottom of the ＂U＂ type curves of which the central wavelength of the area is 1. 55917~m, average group index ng = 721.92 , band gap A）, = 0.35 nm and flat ratio a = 0.02% by calculation. In this paper, we replace the location of first row of air hole in coupled cavity waveguide to investigate the change of low-dispersion slow light. The results not only show that the central wavelength of the area is 1. 60412μm, average group index ng = 41.05, band gap ng = 6.67 nm but also slow light with a maximum group index ng = 2173.12,. maximum group velocity vg = c/2173.12 at wavelength 1. 56177μm are obtained.