High-brightness diodes and fiber-coupled modules

Abstract

We report on continued progress in nLIGHT’s high power and high efficiency single emitter laser diodes from 915 nm to 980 nm range used for industrial and pumping applications. High performance has been demonstrated in nLIGHT’s diode laser technology in this spectral range with peak electrical-to-optical power conversion efficiency of ~65%. These diodes have been incorporated into nLIGHT’s fiber-coupled pump module, elementTM. We have reduced the slow-axis divergence of our brightest diodes by a half at the same operating power. This results primarily from suppression of higher-order lateral modes leading to lower beam-parameter-product at a given power compared to conventional broad area lasers. We have device designs that produce slow axis brightness of up to 4.3 W/mm-mrad which is 48% higher compared to our brightest broad area laser. This paper presents nLIGHT’s most recent improvement in slow-axis brightness resulting from reduced number of allowed modes in the slow-axis in a new broad area laser architecture called reduced-mode diodes (REM-diodes). We will detail the resulting power and brightness improvement along with preliminary reliability assessment of these diodes.