Beam shaping and fiber coupling of high-power laser diode arrays

The extreme divergence and the astigmatism of the high power laser diode array (LDA) require optics with complex lens structure and high performance. A monolithic micro- optic system is designed to shape the beam of LDA and couple the output of LDA with low NA fiber. The structure and principle of the micro-optic system is described in detail. The actual performance of the micro-optic system is studied by measuring P-I properties for both fiber coupled output and the LDA output, and their dependences on deviations in x, y, z directions. The light output of 980nm, 19-emitter LDA is shaped by this micro-optic system and coupled into a fiber with 400µm diameter, Numerical Aperture (NA) 0.22. The overall efficiency is more than 60%. The main factors effecting coupling efficiency are analyzed.