Near-1.3-mum lasers based on multiple layers (2, 5 and 10) of InAs/InGaAs/GaAs quantum dots with high performance have been grown by molecular beam epitaxy. A record differential efficiency as high as 88% was achieved in laser based on 10 QD layers. Threshold current density of 100-150 A/cm(2) and differential efficiency of 75-80% were achieved simultaneously in the same device. Characteristic temperature of 150 K in 20-50degreesC temperature range was demonstrated for the laser based on 5 QD layers. A steep increase in internal loss with decreasing cavity length was found to limit the highest mirror loss possible for ground state lasing. (C) 2003 Elsevier Science B.V. All rights reserved.