Reaserch In Beam Shaping Of Laser Diode Array

Since the high-power laser diode has small volume, light weight, highelectro-optical conversion efficiency, small size, long service life and othercharacteristics that it has wide application prospects in the industry, military and otherfields. However, due to the limits of the laser diode’s own waveguide structure, theoutput beam in fast axis and slow axis is astigmatic and asymmetric beam. In the fastaxis the beam divergence angle reached70degree, the slow axis beam divergence anglealso achieve about10degree. In some high power application, because of the outputpower of the single laser diode is very limited, the laser diode array which composed ofseveral single laser diode is designed to increase the output power. The output beam ofthe laser diode array,which is also astigmatic and asymmetric, must be shaped throughthe optical beam-shaping system.In this thesis, on the basis of current beam shaping methods in domestic andforeign, according to the geometrical optics theory, an aspherical plane-convexcylindrical lens has been designed to collimate the divergence in fast axis for laser diodearray. Correspondly, a titled convex-convex cylindrical lens array has beem designed toshape the beam in slow axis,which breaks the periodic characteristic of the beamdivergence in slow axis and balances the beam quality in both fast axis and slow axis.We have simulated the fast axis collimating lens and the slow axis beam shapinglens in Zemax. According to the result of the simulation, the divergence angle in fastaxis of the laser diode array has reduced greatly after the fast axis collimating lensshaped, and then the collimating beam past through the slow axis beam shaping lens, theperiodic characteristics of the divergence angle in slow axis has broken.According to the result ofd simulation, we take OCLARO’s808-20W diode laseras the laser diode array prototype to build the laser diode array beam shapingexperiment. The result shows that the divergence angle in fast axis has reduce from698mrad to-0.25mrad~+0.25mrad, the beam qulity in fast axis and slow axis has beenuniformed.