Spectral characteristics of single-In/sub 0.7/Ga/sub 0.3/As quantum-well microring lasers

Low-threshold optically pumped microring and disk lasers containing a single compressive strained In0.7Ga/sub 0.3/As quantum well are characterized. Strong bandfilling in single quantum wells is used to show saturation of the background spontaneous emission in microrings compared with comparable microdisks. The continuous wave threshold pump power for a microring is as low as 2 μW (3 W/cm
²
) at liquid nitrogen temperatures. The lasers operate multimoded with wavelengths determined by whispering gallery modes of several orders.