Beam shaping of edge-emitting diode lasers using a single double-axial hyperboloidal micro-lens

We report an innovative approach for beam shaping of edge-emitting semiconductor diode lasers using a single double-axial hyperboloidal micro-lens fabricated with femtosecond laser direct writing technology. The two hyperboloids of different axial lengths focus the light from fast and slow axes to an identical focal spot. The divergence angles were shaped from 60° and 9° to 6.9 and 32.3 mrad, respectively, and the single-end fiber coupling efficiency is measured higher than 80%. The device is simple in fabrication, robust in structure, and easy for operation, by which multiple reflections and absorptions at interfaces are reduced, and assembly errors are minimized.