A laser diode pumped Tm3+-doped ZBLAN fiber upconversion laser is demo
nstrated with blue output power levels up to 106 mW. Differential opti
cal-to-optical conversion efficiencies up to 30% are measured with res
pect to pump power coupled into the upconversion fiber. A single spati
al mode blue output beam is demonstrated, with an M(2) value of 1.4. (
C) 1995 American Institute of Physics.