Beam vignetting effect in micro-optic collimation and transmission for high power diode laser arrays

Abstract

High power diode laser arrays need special micro-optic beamshaping to optimize for collimation and spot focusing. A known and established solution makes use of cylindrical micro-optics for fast axis collimation and subsequent individual twisting of each emitter beamlet by a micro-optic cylindrical telescope array in order to achieve a symmetric beam parameter product. A crucial factor for the overall performance is the achievable transmission to collimation and the fibercoupling efficiency. We present an optical analysis of vignetting effects on the transmission in the beam twisting setup and show an optimization which can be achieved by advanced micro-optic production technologies.