Abstract

Semiconductor microdisks 2 to 5 μm in diameter composed of six 100-Å InGaAs quantum well layers separated by 100-Å InGaAsP barriers are fabricated on InP support pedestals. These disks form high-Q optical resonators for the whispering-gallery mode around the edge of the disk.¹ Optical pumping results in lasing for wavelengths near 1.5 μm with emission both vertically and from the edge of the disk. Threshold pump powers are in the range from 50 to 100 μW. Near threshold the laser emission for the smaller diameter disks varies smoothly with pump power as expected for an optical resonator where the emission is restricted to only a few optical modes. The emission linewidth also varies smoothly with pump power. The measured emission characteristics allow us to model the microdisk emission by using rate equations involving the microresonator Q value and the β parameter, i.e., the ratio of the probability of emission into the lasing mode to the probability of emitting into all modes. We will report Q and β values as a function of disk radius, perfection of the disk edge, the dimensions and shape of the support structure, and the disk temperature for both cw and pulsed excitation. These low threshold microlasers may find application in large arrays and optical interconnects.

© 1992 Optical Society of America