基于FBG的多级延迟SBS结构的慢光系统研究

Stimulated Brillouin scattering based multi-line delay slow light system using fiber Bragg gratings

设计一种基于光纤布拉格光栅(FBG)的多级延迟受激布里渊散射(SBS)结构的慢光系统。实验中采用2个FBG和一段15 km标准单模光纤(SSMF),利用光栅不同的反射特性,使信号光和泵浦光可重复通过同一段光纤相互作用,在仅使用一段光纤情况下达到双级时延的效果,并且FBG对信号光同样具有一定的延迟。实验结果表明,在展宽SBS增益谱的情况下,选取参数合适的FBG,脉冲宽度为1.25 ns的高斯型信号光通过此慢光系统可以获得1.72 ns的延迟时间,最大相对时延为1.01。对比传统采用两段光纤的双级时延结构,在将慢光延迟光纤长度缩短1/2的基础上,延迟性能提高了36.4%。

In this paper a new technique is presented for improving the pulse-delay performance of a stimulated Brillouin scattering（SBS） based multi-line delay structure by using fiber Bragg gratings（FBGs）.Two FBGs and a 15 km-long standard single-mode fiber（SSMF） are used in the structure.We designed the Bragg wavelength and dispersion of the FBGs so that the probe could be amplified by the pump through SBS for several times in the same fiber.The effect of two-line delay structure was achieved.In addition FBG can provide additional delay to the signal.Experimental results show that by optimizing the parameters in this SBS based broadband slow light system using FBGs,a 1.72 ns delay for a 1.25 ns Guassian pulse is achieved,and the maximum fractional delay increases to 1.01 finally.Compared with conventional optical fibers by two double-delay structures,the delay performance of the proposed system is enhanced by 36.4%.