Light-emitting diodes operating at 2 \mu{\rm m} with 10 mw optical power

Light-emitting diodes emitting near 2 \mu{\rm m} producing quasi-continuous wave optical power of {>}{\rm 10}~{\rm mW} at room temperature have been demonstrated. The combination of a strain-engineered quantum well active region and a cascaded injection scheme made it possible to achieve an internal efficiency of 120%. The higher wall plug efficiency of the two-cascade devices indicates that Auger recombination is primarily responsible for the efficiency drop at high injection levels.