在光网络中平顶滤波器可以有效地提高信道光检测的快速性和准确性。利用两个法布里珀罗腔间的串联耦合,可以构建出具有平顶透射特性的双腔型法布里珀罗滤波器。采用传输矩阵的方法,研究了随机生长误差对双腔型平顶滤波器透射特性的影响。模拟分析表明,当两个法布里珀罗腔的物理厚度差超过一个纳米时,在透射谱中就会出现两个高度不同的透射峰;解释了实测器件的透射谱中的双峰不对称性;用界面起伏的概念解释了实测滤波器带宽大于理论值的原因。理论分析与实验结果取得了较好的一致。

In the optical network, a filter with flat-top response can complete the quick and accurate channel optical detection with wavelength. With two Fabry-Pérot cavities coupled in series, a double half-wave filter with flat-top transmission characteristic is demonstrated. The effect of the random growth error on the transmission performance of the double half-wave filter with flat-top response is studied, with the transmission matrix method. The simulation indicates that there appear two peaks with different height in the transmission spectra when the physical thickness difference of the two Fabry-Pérot cavities exceeds 1 nm, which illustrates the two-peak asymmetry in the transmission spectra of the tested devices. In addition, the concept of interface random undulation is used to explain why the measured bandwidth of the filter is larger than the theoretical result.