基于单泵浦源结构的高平坦C+L波段掺Er^(3+)光纤宽带光源

A high flattening C+L band Er^(3+)-doped fiber broadband source with the single pump structure

为了实现高平坦的C+L波段放大的自发辐射光(ASE)光输出,提出并设计了一种基于LD单泵浦源,并且采用两段掺杂浓度完全相同的掺Er3+光纤(EDF)作为增益介质的宽带光源。对光源的基本原理及实现方案进行了理论分析和实验验证。首先,根据Er3+能级结构介绍C+L波段宽带光源的产生原理。然后,设计系统结构,在结构中采用976nm LD作泵浦源,通过耦合器将泵浦光按照一定比例分为两路对EDF泵浦;采用两支波分复用器(WDM)将泵浦光耦合进入EDF,并通过熔接环形镜(FLM)提高转换效率;输出端熔接隔离器(ISO)防止端面回波对输出造成影响。最后,根据EDF的ASE增益数学模型对EDF长度进行了分析和优化。实验结果表明,用于调整C波段ASE光输出的EDF1长选用2m,用于调整L波段ASE光输出EDF2长选为16m,获得平坦C+L波段ASE光输出,在不使用任何滤波器的条件下,在1 540~1 610nm波段范围内光谱平坦度为±0.525dB,在1 520~1 610nm范围内光谱平坦度为±1.119dB。本文方法使用1支976nm LD实现了C+L波段的高平坦输出,简化了系统结构,并降低了系统成本。

In order to realize a high flattening C＋L band amplified spontaneous emission （ASE） light output,an erbium doped Fiber （EDF） broadband source using just one 976 nm Laser Diode （LD） is proposed theoretically and demonstrated experimentally, and the theoretical analysis and experimental verification are presented in details. Firstly, based on the energy level of Er^3＋ , the method of realizing C＋ L band ASE output is presented. Then, the system configuration is designed. One 976 nm LD is used for pumping, and the pump light, which is divided into two parts by one coupler, is pumped into two EDFs with the same concentration. A fiber loop mirror （FLM） is used to improve working efficiency,and two wavelength division multiplexers （WDMs） are also used to couple light into EDFs. Meanwhile, an optical isolator is used to avoid the effect of reflected wavelength from output facet. Finally, based on the mathematical model of the ASE gain,the length of EDF is discussed as well. A high flattening C＋L band ASE source is achieved by optimizing the length of EDF1 which is used to control the power ot C band output and the length of EDF2 which is used to control the power of L band output. In the experiment,2 m EDF1 and 16 m EDF2 are adopted. The flatness of the spectra from 1540 nm to 1 610 nm is ±0. 525 dB,and the flatness is ±1. 119 dB during 1 520-1 610 nm without any filter. The high flattening C＋L band ASE output is achieved by just one 976 nm LD,which can optimize system and reduce the cost as well.