高性能可调谐滤波片的优化设计方法

根据薄膜窄带滤光片在倾斜入射时的特性,通过改进间隔层膜系结构来调整其等效折射率,可以设计出具有稳定透射峰值和带宽的角度调谐窄带滤光片。根据与密集波分复用(DWDM)系统相关的通道频率、插损、带宽、隔离度、偏振相关损耗(PDL)等八个标准,结合薄膜矩阵理论与新构造的评价函数,构建了一个可调谐滤光片膜系,通过改变各参数的权重因子,得到满足不同要求的最优膜系。利用构建的系统,优化设计了分别用于O波段和C波段100 GHz密集波分复用系统的具有高隔离度、低偏振相关损耗的角度调谐窄带滤光片。C波段膜系的最大调谐角度达11°,相邻通道隔离度可达-30.3 dB,最后对其透射特性以及影响调谐角度极限的因素进行了分析。

Optimization Design Method for High Performance Tunable Filter

According to the characteristics of a thin film narrowband filter at oblique incidence, an angle-tunable narrowband filter with stable transmission peak and bandwidth can be designed by improving the structure of spacer film system to adjust its equivalent refractive index. According to the eight standards related to the dense wavelength division multiplexing(DWDM) system such as channel frequency, insertion loss, bandwidth, isolation degree, polarization dependent loss(PDL) and so on, in combination with the theory of thin film matrix and the newly constructed evaluation function, a tunable filter membrane system is constructed, and the optimal membrane systems satisfying different requirements are obtained by changing the weighting factor of each parameter. Using the built system, the angle-tunable narrowband filters with high isolation and low polarization-dependent loss for 100 GHz DWDM system on O-band and C-band are designed. The maximum tuning angle of the film system on C-band is 11°, and the isolation degree of adjacent channels is up to-30.3 dB. Finally, the transmission characteristics and the factors influencing the tuning angle limit are analyzed.