利用传输矩阵法计算了正负折射率交替一维光子晶体的带隙特性。结果表明这种光子晶体具有宽而平坦的禁带,窄而尖锐的通带。这种带隙特性是受到布拉格散射、法布里珀罗谐振和=0禁带共同影响的结果,通带位置决定于法布里珀罗谐振。在理论分析基础上设计出密集波分复用用窄带梳状滤波器,给出信道间隔为0.8 nm的梳状滤波器的仿真结果。仿真结果表明这种梳状滤波器具有信道间隔窄、禁带平坦、通带极窄的特点。信道间隔可以通过改变一维光子晶体单元周期光学厚度调节。

The transmission spectrum of one-dimensional (1D) photonic crystal (PC) with positive-negative index alternant multilayer is studied with transfer-matrix method. The result reveals that this type of 1D PC has broad-flat forbidden band and narrow-sharp transmitted band. The transmission-spectrum character is affected by Bragg scattering, Fabry-Pérot resonating and the =0 forbidden band. The position of transmitted band is determined by Fabry-Pérot resonating. A new narrow-band interleaver applied to dense wavelength division multiplexing (DWDM) system is designed by this type of one-dimensional photonic crystal. The simulation result of 0.8 nm channel spacing interleaver is presented. It is shown that this new interleaver has narrow channel spacing, flat forbidden band and narrow transmitted band. The channel spacing can be adjusted by change of the unit period optical thickness of one-dimensional photonic crystal.