Ultra-broadband optical filter based on chirped long-period fiber grating using leaky mode coupling  

作　　者：XUE Linlin Bras Samuel Malumba Timoteo QIU Weiwei WANG Zhongpeng 

机构地区：[1]School of Information and Electronic Engineering,Zhejiang University of Science and Technology,Hangzhou,310023,China

出　　处：《Optoelectronics Letters》2022年第10期577-582,共6页光电子快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.61405178 and 61505176);the Zhejiang Provincial Key Natural Science Foundation of China(No.LZ21F010001).

摘　　要：An ultra-broadband optical filter was proposed and demonstrated based on leaky mode coupling in a coated chirped long-period fiber grating(CLPFG). The CLPFG was coated with a material whose refractive index(RI) was higher than that of the fiber cladding, enabling the coupling of the core mode to leaky modes, to achieve a desired coupling efficiency. Complex coupled-mode theory was used to investigate the power evolution of the core mode that resulted from the coupling. From this, the conditions in which the core mode power attenuates the most rapidly were identified. In addition, phase matching turning point(PMTP) was used in the design, to overcome the conflict between the range of grating period change and the grating length in the CLPFG. Finally, an optimized CLPFG-based filter with a length of 3.5 cm was obtained, which has a symmetrical attenuation band with an operating bandwidth over 300 nm. Within the operating bandwidth, the flatness is less than 2.5 d B and the transmittance is lower than 0.1%.

关 键 词：FIBER FILTER MODE 

分 类 号：TN253[电子电信—物理电子学] TN713