光纤长度优化的高功率铒镱共掺光纤放大器

High power Er^(3+)/Yb^(3+) co-doped fiber amplifiers with optimum fiber length

为了研究不同增益光纤长度下1555nm高功率光纤放大器的输出功率,采用两级混合结构的方法,用掺铒光纤放大器和双包层铒镱共掺光纤放大器分别作为1级预放大器和2级主放大器。掺铒光纤放大器对信号光进行预放大,并提高放大器的信噪比;双包层铒镱共掺光纤放大器为主放大器,其双包层结构可以把更多的多模抽运光耦合进系统。对铒镱共掺光纤的最佳长度做了理论分析和实验验证,在信号光功率为10mW、掺铒光纤放大器的抽运功率为318.58mW、双包层铒镱共掺光纤放大器的抽运功率为11.71W、增益光纤长度为14m时,输出功率取得了2.11W的实验数据。在分析输出信号光谱时发现,L波段附近有放大自发辐射谱出现,这是选择的增益光纤过长导致的。结果表明,在光功率和信号光功率一定时,光纤放大器有一个最佳的光纤长度。这一结果对研究光纤放大器的高功率输出是有帮助的。

In order to investigate 1555nm high power fiber amplifiers with different gain length, a two-stage hybrid structure was employed, in which an erbium-doped fiber amplifier（EDFA） was used as a pre-amplifier for signal amplification and higher signal-noise ratio and an erbium/ytterbium co-doped double-cladding fiber amplifier （EYCDFA） was used as a master amplifier. The EYCDFA with special double-cladding configuration can couple more pump power into the system. The optimal length of erbium-ytterbium co-doped fiber was investigated experimentally and analyzed theoretically. Under the conditions of 10mW signal power, 318.58mW EDFA pump power, ll.71W EYCDFA pump power and 14m gain length, 2. llW output power was achieved. Amplified spontaneous emission spectrum appeared in L-band because of the over long gain fiber. It shows that there exists an optimal length at certain pump power and signal power, and the result is good for the study of high-power fiber amplifiers.