Diffraction-limited emission from a diode laser array in an apertured graded-index lens external cavity

Abstract
A gain-guided coupled-stripe GaAs/GaAlAs diode laser array in an external cavity configuration consisting of a graded refractive index lens and a 25-μm stripe apertured mirror was studied. Output power of almost 500 mW was obtained from the cavity under pulsed operation. A centered, single-lobed far-field radiation pattern which did not steer with the drive current was observed up to 4.1Ith. At 2Ith approximately 94% of the 102-mW output power is contained in the 0.8° full width half-maximum central lobe.