Laser diode pumped Pr/sup 3+/-doped and Pr/sup 3+/-Yb/sup 3+/-codoped fluoride fiber amplifiers operating at 1.3 mu m

Both Pr3+-doped and Pr3+-Yb3+-codoped singlemode fibres with high numerical apertures are pumped by laser diodes with InGaAs/GaAs strained quantum well structures. A net gain of 5.2 dB is obtained from Pr3+-doped fluoride fibre pumped by laser diodes operating at 1.017 μm and a net gain of 3.2 dB is obtained from Pr3+-Yb3+-codoped fibre pumped by laser diodes operating at 0.98 μm. The pumping efficiency difference between Pr3+-doped and Pr3+-Yb3+-codoped fibre is discussed.