Improvement of spectral efficiency based on spectral splitting in photonic quantum-well structures

The multiple photonic quantum-well structures are proposed by breaking the periodicity of a one-dimensional photonic crystal, in which the effect of spectral splitting is clearly observed. On the basis of the finite-difference time-domain method, the physical origin of the spectral splitting is explained, and the regularity of the formation of the multiple peaks is analysed. It is also found that both the well and barrier thicknesses have a marked influence on the positions and the number of the split peaks, and their relationships are carefully discussed. By using these proposed structures, the number of transmission peaks can be increased multiplicatively, and their spectral spacing can be finely tuned, resulting in high efficient utilisation of photonic band gap.