High brightness, high efficiency laser sources become more and more promising in diode laser applications for fiber laser pumping and materials processing. Dense wavelength beam combining (DWBC) technology has great advantages over other beam combining technologies as the brightness is significantly improved. However, the brightness and efficiency of DWBC technology based on laser diode bars are naturally limited by the laser source due to smile effect and low polarization ratio. By employing single emitter based DWBC technology and optimizing the optical design, a laser diode module capable of delivering above 600 W at 976 nm in a 0.22 NA 100/120 fiber is developed and 48% power conversion efficiency is achieved. The maximal power conversion efficiency, 51%, is reached at 400 W output. The intrinsic wavelength stabilization of DWBC technology allows the use of the module for efficiently pumping.
The paper reports on the design and development of an innovative high power and high brightness laser diode module that is capable of delivering more than 350 W at 976 nm in a standard 0.2 NA 50/125 fiber and 95% of power is in 0.15 NA. This module combines Everbright's multi-emitter modules assembled with 50 μm ridge width 976 nm laser diode chips through dense wavelength beam combining (DWBC) and polarization combining. The intrinsic wavelength stabilization of DWBC technology allows the use of the module for efficiently pumping Yb-doped fiber lasers.