100 W/100 μm passively cooled, fiber coupled diode laser at 976 nm based on multiple 100 μm single emitters

We developed a high brightness fiber coupled diode laser module based on single diode lasers providing more than 60 Watts output power from a 100 micron fiber at the optimum fiber laser pump wavelength of 976 nm. The advantage of using multiple single emitters on a submount compared to using bars or mini bars is the direct fiber coupling by use of optical stacking and the fact that no beam transformation is needed. We achieved best brightness with a high fill factor, optical efficiency of more then 80% and wall-plug efficiency of more then 40%. The use of single emitters on a submount also extends the life span due to reduced failure (x ⁿ vs. x) per device (n individual emitters vs. n emitters on a bar (mini array)). Low drive current enables modulation. In this paper we present the optical and mechanical design of the module, the alignment stage and process as well as the experimental results of power, spectrum, wavelength shift and total efficiency measurements.