MIDINFRARED FLUORIDE FIBER LASERS IN MULTIPLE CASCADE OPERATION

CW fiber laser cascades in an Er3+-doped fluorozirconate fiber operating simultaneously at 2.7 mum/1.55 mum or at 3.45 mum/2.7 mum/1.55 mum pumped around 650 nm are reported. Output powers of nearly 20 mW at 1.55 mum and 1.2 mW around 2.7 mum were obtained with a nonoptimized experimental setup for the 2.7 mum/1.55 mum cascade. At 1.55 mum a laser efficiency of 5% was achieved. By varying the parameters of the experimental setup, additional effective simultaneous laser action at 3.45 mum was demonstrated.