渐变折射率光量子阱对束缚态能级的调整

在对称的均匀电介质材料光子晶体体系中插入另一折射率渐变的光子晶体可构成光量子阱结构.利用时域有限差分法计算了不同折射率分布光量子阱结构的传输谱.研究表明：束缚态是对处于垒光子晶体禁带中的阱光子晶体导通带的离散化,束缚态能级个数等于阱光子晶体结构单元的重复周期数；以渐变方式调整阱区折射率分布,可在特定频率范围内得到新的互不交叠的束缚态.这样在有限的禁带区域可以成倍增加光子束缚态而无需增大光量子阱结构的尺寸,使信道密度最大化、光波有效带宽的使用最优化.这种量子阱结构可用于制作超窄带滤波器和多通道窄带滤波器,有望在光通信超密集波分复用和光学精密测量技术中获得广泛应用. 关键词： 光量子阱 光子束缚态 渐变折射率 光子晶体

Modulated photon confined states with graded-index photonic quantum well structure

The formation of a photonic quantum well structure by sandwiching a graded-index photonic crystal between two symmetrical constant-index photonic crystals is demonstrated. The transmission spectra of various quantum wells with different refractive index profiles in the well region are calculated by finite-difference time-domain method. The results show that the observed fine peaks are quantized states of a photonic band, provided the photonic band of the photonic crystal in the well region is just located in the photonic band gap of the photonic crystal in the barrier region. It is found that the number of the quantized states are equal to the number of periods of the well region, the un-folded new confined states can be obtained by adjusting profile exponent in a given frequency region, in this way the multiple photon confined states can be gained without increasing the size of quantum well structures within limited forbidden band gap region. This method can lead to the maximization of channel density and optimization of the use of effective bandwidth. This structure can be applied to built super-narrow band optical filter and multi-channel narrow band optical filter, it may find application in super-dense wavelength division multiplexing for optical communication and precise optical measurement.