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-We report on the design aspects of high performance diode lasers for application in highbrightness spectral beam combining and coherent beam combining modules. Key performance trade-offs are identified and potential solutions are explored.

The performance of high-brightness laser diode emitters and bars is often affected by external optical feedback from the modules and systems in which they are deployed. We report on the coupling of an advanced simulation tool for highbrightness laser diodes with commercial optical design software. The aim of this work is to create a software tool which can be applied to the design and optimisation of high-brightness diode laser modules and systems intended for use in industrial applications requiring the cutting and welding of sheet metal.

We describe a new coherent beam combining architecture based on passive phase-locking of two laser diodes in a Michelson external cavity on their rear facet, and their coherent combination on the front facet. As a proof-of-principle, two ridge lasers have been coherently combined with >90 % efficiency. The phase-locking range, and the resistance of the external cavity to perturbations have been thoroughly investigated. The combined power has been stabilized over more than 15 min with an optical feedback as well as with an automatic adjustment of the driving currents. Furthermore, two high-brightness high-power tapered laser diodes have been coherently combined in a similar arrangement; the combining efficiency is 70% and results in an output power of 4 W. We believe that this new configuration combines the simplicity of passive self-organizing architectures with the optical efficiency of master-oscillator power-amplifier ones.