Superluminescence in InAsSb circular-ring-mode light-emitting diodes for CO gas detection

We report on the superluminescence of an InAsSb light-emitting diode, operating at 4.6 μm, suitable for carbon monoxide gas detection. The source is based on an optical whispering (or circulating) mode which is generated near the edges of the mesa and which is responsible for the superluminescence. A pulsed optical output power in excess of 2.2 mW at room temperature has been measured, making these emitters suitable for use in cost-effective instruments for the environmental monitoring of carbon monoxide at 4.6 μm.