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设计了一种二维三角晶格光子晶体共振耦合腔波导,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1.54538μm处群折射率ng=725.93、群速度vg=c/725.93的慢光。该光子晶体共振耦合腔波导传输光的群折射率随波长变化关系呈现“U”型结构,在“U”型底部出现低色散慢光区域。计算表明“U”型底部区域波段为中心波长1.54720μm、平均群折射率n珘g=142.6、带宽Δλ=2.16nm、平坦率σ=3.20%的低色散慢光。通过移动耦合腔波导第一排空气柱的位置研究低色散慢光的变化,结果表明,移动耦合腔波导第一排空气柱的位置,使得“U”型底部区域波段中心波长在1.54720～1.60549μm范围内变化,可产生平均群折射率n珘g由142.6变为26.7、带宽Δλ由2.16nm增大为15.21nm的低色散慢光。
A two-dimensional triangular lattice photonic crystal resonator coupled cavity waveguide was designed. The transmission spectrum of TE polarized light was calculated by finite-difference time-domain (FDTD) simulation. The group refractive index ng = 725.93 at wavelength 1.54538μm and the group velocity vg = slow light of c / 725.93. The group refractive index of the light propagating through the photonic crystal resonator coupled cavity waveguide shows “U ” type structure with the wavelength variation, and the low-dispersion slow-light region appears at the bottom of the “U ” type. The calculation shows that the bottom band of “U” type has low dispersion and slow light with center wavelength of 1.54720μm, average group refractive index n 珘 g = 142.6, bandwidth Δλ = 2.16nm and flatness σ = 3.20%. The results show that the position of the first row of air column of the moving waveguiding waveguide is such that the center wavelength of the “U” type bottom region band is between 1.54720 ~ 1.60549μm, it can be found that the average group refractive index n 珘 g changes from 142.6 to 26.7, and the bandwidth Δλ increases from 2.16nm to 15.21nm.