Abstract:

Fabrication process of efficient Er³⁺:Yb³⁺ co-doped phosphosilicate fibers by modified chemical vapor deposition (MCVD) was reported. The process is combined with the solution doping technique where the codopant of aluminum is absolutely removed. It shows that the backward deposition process can be adapted to incorporate low viscosity phosphate glass and the reason of the porous layer with a higher phosphorus content which is fabricated in that process was discussed in details. The limiting of the back-transfer of energy from erbium ions to ytterbium ions and the suppressing the onset of Yb-ASE are demonstrated by fluorescence spectrum of the perform of phosphosilicate. It shows the efficient energy transfer in this broad absorption, ytterbium-sensitized erbium fiber. The performances of double-cladding Er³⁺:Yb³⁺ co-doped fiber lasers (EY-DCFLs) are also studied experimentally. The maximum output power is about 3.2 W by using a 4 m fiber, with a slope efficiency of 30%.

Key words: backward deposition, MCVD, Er³⁺:Yb³⁺ co-doped, phosphosilicate