Coherent High Power Diode Laser Array

In this proposal, nLight and its collaborator, Prof. Kent Choquette, of the University of Illinois, seek to directly address limiting factors which have prevented the development of coherent high power diode laser arrays. The proposed approach leverages a novel method of fabricating in-phase coherently-coupled VCSEL arrays combined with high power packaging based on microchannel cooler technology. The laser design utilizes high density gain pixilation introduced by small proton-implanted current confinement apertures. What makes this approach fundamentally different than the others before it is this gain pixilation is performed with little-to-no optical loss introduced between adjacent emitters. This allows the arrays to lock up in the preferred in-phase supermode (with on-axis intensity peak in the far-field), without the need to individually address and control relative phasing of constituent emitters. These high-density coherent VCSEL arrays will then be In-soldered to Cu microchannel coolers, and power scaling can then be achieved by simply scaling the area of the array, with preliminary calculations suggesting powers as high as 1 kW are realizable from a 1 cm x 1 cm chip.