一种导模共振窄带宽的平顶滤波器设计

鉴于导模共振滤波器具有高峰值反射率、低旁带反射、窄带以及带宽可控等优良特性,采用亚波长光栅的导模共振效应设计了一种平顶滤波器。通过将亚波长光栅与类法布里-珀罗腔结合使用,实现了窄带宽平顶滤波的效果。基于严格耦合波分析方法和等效介质理论,使用FDTD软件对光栅衍射效率进行了仿真分析。仿真结果表明,平顶滤波器在1 130 nm处可获得2 nm宽的平顶,同时半高全宽达到6 nm,透射效率达到98%。通过微机电系统可以线性调节类法布里-珀罗腔的厚度,该器件可调谐的波长范围为1 130～1 300 nm,可应用于光通信、光开关等领域。

A narrowband flat-top filter based on guided-mode resonance effect

A guide mode resonance device represents a unique class of filters that can reflect a narrow resonance band with almost 100% efficiency and low sideband. In this paper, a flat-top filter is designed using the guided-mode resonance effect of the sub-wavelength grating.By combining it with a Fabry-Perot-like cavity, the effect of narrow-bandwidth flat-top filtering is realized.The transmission spectrum of the proposed filter shows a flat-top width of 2 nm and a full width at half maximum of 6 nm can be obtained. The spectrum shows good rectangularity and suppressed sidebands with the transmittance up to 98%. In the simulation, the microelectromechanical system can be used to linearly adjust the thickness of the Fabry-Perot-like cavity, realizing the tuning characteristic of the resonance peak wavelength between 1130 and 1300 nm.The device has potential applications in the fields of optical communication and optical switches.