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Vertical cavity surface emitting lasers (VCSELs) have been widely used in optical recognition, optical communication, optical storage and other fields owing to their unique circular symmetrical spot, small volume and ease of high density array integration. In this paper, with the array beam collimated by compound lens, the beam distribution and far-field characteristics of VCSEL array are analyzed. In addition, the beam quality characteristics of VCSEL array are also studied, and the effects of different lenses combinations on the beam divergence angle and spatial coherence of VCSEL array are compared and discussed. The results show that the divergence angle of VCSEL array gradually increases with the increase of injection current, while the spatial coherence of VCSEL array decreases. For the 10 × 10 VCSEL array with an oxidation aperture of 10 um and a center distance of 130 um, when working at 200 mA , the beam divergence angle decreases from 21.8° to 0.2°, the beam coherence increases from 0.556 to 0.861, and the coherence increases by 54% after collimation by the composite lens , which is of great significance to improve the application of VCSEL array light source in free space coherent detection and optical communication.
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