Ho³⁺/Pr³⁺Co-Doped AlF₃Based Glass Fibers for Efficient 2.9 μm Lasers

In this letter, we demonstrated efficient 2.9 lasing in Ho3+ /Pr3+ co-doped AlF3 based glass fibers. The Ho3+/Pr3+ co-doped fibers were fabricated by using a rod-in-tube method based on the AlF3- BaF2- YF3 - MgF2- PbF2 glass. By using a 50 cm long Ho3+/Pr3+ co-doped AlF3 based glass fiber as the gain medium and an 1120 nm fiber laser as the pump source, lasing at 2868 nm was obtained, the obtained maximum unsaturated power was about 189 mW for a launched pump power of 1.28 W, and the corresponding slope efficiency was 15.3%, which was three times as high as that derived from singly Ho3+-doped AlF3 based glass fibers. Our results indicated that Ho3+ /Pr3+ co-doped AlF3 based glass fibers were promising gain media for constructing efficient 2.9 fiber lasers.