Modeling of Cascade Lasing in Dy : Chalcogenide Glass Fiber Laser With Efficient Output at 4.5 μm

The performance of a continuous-wave Dy:GeAsGaSe chalcogenide glass fiber laser operating on the6H11/2rarr6H13/2transition at 4.2-4.7 mum is studied using numerical modeling. A double-clad fiber geometry is assumed, with direct pumping of the6H11/2level at 1.7 mum. It is shown that simultaneous lasing on the6H13/2rarr6H15/2transition serves to effectively depopulate the6H11/2level and significantly improve the efficiency and power scalability. A slope efficiency of 0.16 is calculated when the fiber loss is 1 dB/m. For efficient operation, it is necessary to keep the fiber loss below ap5 dB/m.