Study on the Gently Confined Hexagonal Photonic Crystal Cavity with High Quality-factor

The photonic crystal(PhC) cavities with whispering-gallery mode have got more attention by researchers. For increasing Quality-factor(Q factor), we optimize the second round air-holes of the H2 photonic cavity which has been already optimized the first round air holes. And we get 60% Q factor increasing. By researching the third and fourth round air-holes structures, we find out that the effect of confinement of light by round air-holes structure conflict with the effect by photonic crystal. The Q factor do not always increase with the rounds increasing by round air-holes structure.