Power scalable and efficient 790-nm pumped Tm3+-doped fiber lasers

This report presents a discussion of the engineering issues and results of high power 2μm Tm³⁺-doped fibre lasers pumped at 790nm. To date we have achieved up to 85W from such devices with 54% slope efficiency relative to launched pump. More recently, through using Tm³⁺ concentrations of approximately 4(wt.)% to enhance the cross-relaxation process (³H₄,³H₆->³F₄,³F₄) we have demonstrated slope efficiencies of up to 67% relative to launched power. This represented ~170% quantum slope efficiency for the 790nm pumped 2μm laser.