EFFICIENCY OF ERBIUM 3-MU-M CRYSTAL AND FIBER LASERS

The population dynamics of erbium 3-mu m crystal and fiber lasers are compared experimentally and theoretically, Laser slope efficiencies of 40% in Er:LiYF4 and 23% in a fluorozirconate fiber are experimentally demonstrated under Ti:sapphire pumping, These are both to our knowled ge the highest values reported so far for the different host geometrie s, On the basis of the excitation and loss mechanisms, the best pump w avelengths are determined to be 970 nm in LiYF4 and 791 nm in a fluoro zirconate fiber, The theoretical limit of the slope efficiency with re spect to absorbed pump power is redefined as depending on the major po pulation mechanisms of the system, Calculated values are 56% in Er:LiY F4 and 27% in a fluorozirconate fiber.