편광상이 고리 구조 기반 고차 광섬유 유연 빗살 필터에 대한 연구

Abstract

A high-order fiber flexible comb filter is newly proposed, which is based on a polarization-diversity loop structure. The proposed filter (1st-order and 2nd-order filter) consists of a polarization beam splitter, half-wave plates (HWPs), and high birefringence fibers (HBF) segments. In the previous high-order comb filter based on the PDLS, HBF segments were fusion-spliced with a fixed angle offset between their principal axes with each other. But, the proposed high-order fiber filter composed by inserting HWPs between principal axes of HBF segments has a great flexibility in adjusting relative angular difference between the principal axes of adjacent HBF segments. Owing to this flexibility, high-order transmission spectra, which had a channel spacing of ~0.8 nm, could be interleaved by controlling the orientation angles of HWPs The output transmission spectra of the proposed filters were theoretically analyzed and experimentally verified.