High power, narrow bandwidth and broadly tunable Tm3+, Ho3+-co-doped aluminosilicate glass fibre laser

A multiple-watt Tm³⁺, Ho³⁺-co-doped aluminosilicate glass fibre laser operated in narrowband (<;; 0.5 nm) and tuned across a range exceeding 280 nm is presented. For long fibre lengths, tuning from Tm³⁺-dominated to Ho³⁺-dominated was characterised by a transition from stable pulsing to weakly modulated emission. At 2040 nm, maximum slope efficiency and average output power were 25% and 6.8 W.