Highly efficient hybrid fiber taper coupled microsphere laser

A novel hybrid fiber taper is proposed and demonstrated as the coupler in a microsphere laser system. The pump wave and the laser emission, respective ly, are more efficiently coupled to and from the sphere modes with this tap er structure. A 980-nm pumped erbium-ytterbium codoped phosphate microspher e laser is demonstrated in the 1550-nm band. As much as 112 muW of single-f requency laser output power was measured, with a differential quantum effic iency of 12%. (C) 2001 Optical Society of America.