Abstract

Commercial gain-guided diode lasers usually provide far-field patterns with poor optical quality. This is due to the presence of two plane-wave output components' that are tilted with respect to the optical axis. We propose to modify the output facet properties of a diode laser to obtain an output beam with a narrow single-lobe far-field distribution. Numerical simulations have been performed to predict the effects of replacing the standard output facet by a laterally varying reflectivity facet, a spherical and a phase conjugate facet. A facet with an inverted Gaussian reflectivity profile reduces the far-field width of the wide-stripe diode laser but increases the threshold current. With a phase conjugate mirror, the beam root mean square angular width and the threshold current are, respectively, 20 and 50 % lower than with a standard facet. Spherical concave output facets give best results: the far-field width is reduced by 75 % in some configurations.

© 1987 Optical Society of America