Microdisk lasers with three InGaAs/InAlGaAs quantum wells were demonst
rated for the first time. The selective etching method to fabricate th
e InGaAs/InAlGaAs microdisk laser structure is discussed. The lasers w
ith 20 mu m in diameter lase with single mode at 1.5-mu m wavelength w
hen optically Pumped with pulsed Argon-ion laser at 80 K.