Visible (639 nm

The demonstration of InAlGaP visible VCSEL (vertical cavity surface emitting laser) diodes is reported. The structures were grown by MOVPE (metalorganic vapor-phase epitaxy) on GaAs substrates and consist of an InAlGaP optical cavity active region surrounded by AlGaAs DBRs (distributed Bragg reflectors). Gain-guided 'etched post' test devices were fabricated. A top annulus contact defines emitting diameters of 10 mu m and 20 mu m with a 5 mu m radial thickness; thus, a large percentage of the injected current does not directly contribute to lasing but to device heating. Despite this, lasing wavelengths from 639.1 nm to 660.7 nm were measured on unrotated wafers, at room temperature without heat sinking. The pulsed excitation was approximately 100 ns pulses at 10 kHz to 1 MHz. Many devices continued lasing with up to a 40% duty cycle at 1 MHz. The larger devices typically have a threshold of 30 mA at 2.7 V. The peak output power is 3.38 mW with a resistance of less than 15 Omega.