摘 要:随着光通信系统的不断发展, 波分复用(WDM)技术不断进步,包括光学滤波器在内的光学器件不断被改进和应用。其中可调谐法布里一泊罗滤波器 (FPF)在光通信中得到了广泛的应用。铁电材料聚偏氟乙烯(PVDF)及其共聚物P(VDF-TrEE)由于高介电、热释电性能以及柔软、价格便宜、可塑性好等优点,而得以广泛应用。
本文设计了一个法布里一泊罗滤波器,其结构为反射镜/电极/间隔层/电极/反射镜,间隔层采用75/25mol%共聚物P(VDF-TrEE),而反射镜为分布式布拉格反射镜(DBR),即利用周期结构光子晶体的禁带特性。利用传输矩阵理论研究了该滤波器的传输特性。研究表明,通过改变间隔层两端的电压可以改变聚合物的应变,从而对法布里一泊罗腔进行调制,使得腔模波长发生改变。通过数值模拟得到了腔模波长随电压的变化规律,利用这一规律可以设计调谐滤波器。
关键字:传输矩阵,滤波器;P(VDF-TrEE);法布里一泊罗腔
Abstract:With the continuous development of the optical communication system,the WDF technology continues to progress ,optical devices including optical filters are condtantly improved and application. The tunable Fabry-Perot filter(FPF) has been widely used in the optical communication. Polyvinylidene fluoride(PVDF) and its copolymer P(VDF-TrEE), due to their merits,such as high voltage electric, pyroelectric properties and softness, cheap price, good plasticity ,they are used to the space layer of FPF.
This paper describes the design of a Fabry-Perot filter, the structure is reflector / electrode / spacer layer / electrode / reflector, the spacer layer using the 75/25mol% copolymer P ( VDF-TrEE ), and the reflector is a Distributed Bragg Reflector ( DBR ), namely the use of photonic crystal forbidden band characteristic. Using the transfer matrix theory , we study the transmission characteristics of FPF. It shows that the polymer can change the strain by changing the voltage of spacing at both ends of cavity, which can modulation the Fabry-Perot cavity at the same time ,this can make the cavity wavelength changing. Through the numerical simulation, we obtain the regulation of cavity wavelength changing with voltage ,this will design a tuned filter.
Keywords: transmission matrix; filter; P(VDF-TrEE); Fabry-Perot cavity