一维光子晶体偏振滤波器通道数的影响因素研究

光子晶体偏振滤波器是利用光子晶体带隙特性来控制信号光偏振状态的一种新型滤波器, 在光纤通信、光学传感测量、光学信息处理等领域均有重要应用。通道数多少是偏振滤波器设计的重要指标, 通道越多则信息容量越大, 越有利于系统的小型化微型化。利用光学传输矩阵法研究了影响一维光子晶体偏振滤波器通道数目的因素, 研究表明：(1）光子晶体缺陷层厚度是影响滤波器通道数目的关键因素, 通道数N与厚度D近似满足线性关系, 在500 ～650 nm波段函数关系为N=0.0035D+0.159; (2）缺陷层折射率nc的变化也会导致通道数改变, 折射率越大通道数越多;( 3）光子晶体单元层数和单元厚度改变不会影响滤波通道数, 但可以调节通道中心波长位置, 同时对偏振度和分离度也有影响。

Influence Factors on Channel Number of 1D PC Polarization Filter

Photonic crystal (PC) polarization filter is a new kind of filter that can control the polarization state of the signal light by using the photonic band gap. It has important applications in optical fiber communication, optical sensing measurements, optical information processing and other fields. The channel number is an important parameter for polarization filter design. The more the channel number is, the greater the information capacity is. So it is conducive to system miniaturization. The influenced factors on channel number of 1D PC polarization filter are studied by using the optical transmission matrix method, the results show that: (1) The defect layer thickness is the key factor in affecting the channel number, and channel number N is a approximate linear function of the thickness D. In the wavelength band from 500 nm to 650 nm the function is N= 0.0035D+0.159; (2) The change of refractive index in defect layer also leads to the change of channel number, and the greater the refractive index is, the more the channel number is. (3) The changes of the numbers and the thickness of photonic crystal periodic layer cannot affect the channel number, however it can regulate the central wavelength of filter channels and influence the polarization degree and separation degree of polarization.