用时域有限差分法研究了一维光子晶体多量子阱中的谱线分裂现象,揭示了光子隧穿多量子阱时谱线分裂的规律性。研究发现,谱线分裂是阱间相互耦合的结果,其特征不仅取决于势阱的个数,而且与垒区和阱区的几何参量密切相关。计算结果表明,对称多量子阱结构中,光子隧穿p个势阱时,单阱对应的每条透射谱线会分裂为p条,各分裂谱线互不交叠。这样在有限的禁带区域可以成倍增加光子束缚态,使信道密度最大化,光波有效带宽的使用最优化,有望在光通信超密集波分复用和光学精密测量中获得广泛应用。
The phenomenon of spectral splitting in multiple quantum well (MQW) structures composed of one-dimensional photonic crystals is investigated by finite-difference time-domain method. The regularity of splitting is analyzed. It is found that the spectral splitting is induced by the coupling effect of the wells. whose features are determined not only by the well numbers but also by the parameters of barriers and wells. The results indicate that, in the symmetrical photonic MQW structures, each transmission spectrum will split into p different frequencies, where p is the number of the wells in MQW structures. These split spectra are un-folded mutually. In this way, photon confined states can be increased multiplicatively within forbidden band gap region with the maximization of channel density and optimization of effective bandwidth. It may be applied widely in the fields of super dense wavelength division multiplexing for optical communication and the precise optical measurement.