Study on improving the efficiency of superfluorescent Yb-doped fiber source operating near 980 nm with distributed side-coupled cladding-pumped fiber

Abstract The high-power 980-nm superfluorescent Yb-doped fiber source (SYFS) fabricated with the distributed side-coupled cladding-pumped (DSCCP) fiber is studied with the purpose of improving its efficiency. In experiment, by strengthening the pump light coupling of DSCCP fiber, more-than 23% slope efficiency with the record value of 23-W 980-nm emission is obtained. By means of the numerical study, it is revealed that the 980-nm SYFS efficiency can also be enlarged by optimizing the dopant concentration even with the relatively weak pump coupling, which provides an alternative way to improve the efficiency of SYFS. The pertinent results can be of great importance for studying and designing the 980-nm Yb-doped fiber source.