Abstract

We have achieved electrically-pumped lasing at room temperature in microresonators 1.5-5 μm in diameter on a 3×8 mm² chip which contains several hundred thousand lasers. Yield on the chip is very high and the reliability is sufficient to allow a portable demonstration to be scheduled. The microlasers (μlasers) have an active medium containing three quantum wells of 80 Å Ing_0.2Ga_0.8As with 100 Å GaAs barriers. The smallest lasers thus have active material volumes <0.05 μm³. The mirrors were GaAs/AlAs quarter-wave stacks with 20.5 pairs on the bottom n-doped and 12 pairs, p-doped, on top. Additionally the top mirror had a fraction of a quarter wave AlAs, 30 Å δ-doped GaAs, and was capped by 1500 Å Au. The semiconductor heterostructure was grown by molecular beam epitaxy, and chemically assisted ion beam etching etched through the Au cap and the >5 μm heterostructure. Our setup uses white light to illuminate the etched side of the μlaser array which is imaged onto a CCD camera and displayed on a TV monitor. The shadow of an electrical probe tip used to activate the lasers is also viewed and when the top of a μlaser is contacted, its bright output is clearly seen. Translating the μlaser array underneath the probe tip allows us to "yield test" several dozen lasers in a few seconds. Lasers from all regions of the chip appear to operate quite uniformly. The number of lasers on the chip are sufficiently large to allow us to demonstrate destructive overdrive of some of the lasers without concern of running out of them. On another chip with similar μlasers we show CW operation.

© 1989 Optical Society of America