Tuning, temporal, and spectral characteristics of the green (/spl lambda//spl sim/549 nm), holmium-doped fluorozirconate glass fiber laser

The output power, tuning and temporal behavior of the green (539-550 nm), Ho-doped fluorozirconate glass (ZBLAN) fiber laser pumped in the red (/spl lambda//spl sim/643 nm) has been examined in detail. Fibers ranging in length from /spl sim/20-86 cm have been studied, and more than 38 mW of output power has been obtained from a 21 cm long fiber for 30% output coupling and 280 mW of absorbed pump power. By inserting two prisms into the optical cavity, the oscillator has been tuned over /spl sim/11 mn, and the emission spectrum of the free-running laser has been recorded as a function of pump power at both room temperature and 77 K. The self-pulsing (spiking)behavior of the laser and the influence of depletion of the Ho/sup 3+/ ground state (/sup 5/I/sub 8/) population on the emission spectrum and efficiency of this system are discussed.