采用大模面积双包层掺镱光纤作为增益介质搭建了一台双程前向超荧光光纤光源, 该光源的输出功率随泵浦源注入电流的增加基本呈线性增加, 最大输出功率为341 mW。 其独特的优势是现实了掺镱光纤最宽的超荧光输出, 在输出功率从201～341 mW之间, 超荧光光谱的3 dB带宽超过80 nm。 其输出功率虽然不是很高, 但是在一般情况下能够满足人们对超荧光的需求。 从镱离子的能级结构和镱离子在石英基质中的吸收截面与发射截面出发, 分析了能够得到最宽超荧光输出的物理原因。 这台双包层掺镱超荧光光纤光源由于充分利用了镱离子在1 025和1 075 nm附近的超荧光辐射, 因而能够得到3 dB带宽为80 nm的超荧光输出。

The present paper reports a double pass forward superfluorescent fiber source （SFS）, which uses a length of large mode area double cladding ytterbium doped fiber as gain medium. The maximum output power of this SFS is 341 mW. With the output power between 201 and 341 mW, the 3dB bandwidth of this SFS was more than 80 nm. This is the widest 3 dB bandwidth obtained from ytterbium doped SFS. The output power of the SFS linearly increased with the increment of the pump source injected current. It’s output power is not very high, but under normal circumstances, it could meet the needs of the SFS. From the energy level structure of ytterbium ions and the absorption cross-section/emission cross section of ytterbium ions in quartz substrate, the physical mechanisms responsible for superfluorescence were analyzed. This double-cladding ytterbium-doped superfluorescent fiber laser benefits from the superfluorescence radiation near 1 025 and 1 075 nm, so the superfluorescence with 3 dB bandwidth reaching up to 80 nm could be obtained.