Abstract

Two-dimensional arrays of vertical cavity surface emitting lasers (VCSELs) were prepared by patterning the reflectivity of the laser's back mirror.¹ The latter was accomplished by the deposition of metal layers on top of the Bragg mirror, while employing a predefined spatial pattern. High-quality and very large laser arrays were obtained using this method.² In this paper we report the results of a study of VCSEL arrays, in which the laser size is not uniform. The tapering we employed here was based on changing the laser size according to the two-dimensional (2D) Hermite polynomial. The Hermite tapering was chosen because of several reasons: The Hermite-Gaussian modes are the approximated lasing modes of rectangular broad-area lasers, thus the Hermite tapered laser array was expected to lase in this preferred mode, unlike the conventional anti-phase mode of regular arrays; predefined Gaussian-Hermite modes can be used in various applications since they preserve their functional intensity pattern during propagation. As a consequence, these laser arrays can be exploited for array illumination by multiple light beams, while the far-field of a regular (non-Hermite tapered) array always consists of only 4 intensity lobes.²

© 1994 IEEE