Rear-side resonator architecture for the passive coherent combining of high-brightness laser diodes

Guillaume Schimmel (1) , Ioana Doyen-Moldovan (1) , Sylvie Janicot (1) , Marc Hanna (1) , Jonathan Decker (2) , Paul Crump (2) , G Blume (2) , Götz Erbert (2) , Patrick Georges (1) , Gaëlle Lucas-Leclin (1)

1 Laboratoire Charles Fabry / Lasers
2 FBH - Ferdinand-Braun-Institut für Höchtstfrequenztechnik

We describe a new coherent beam combining architecture based on passive phase-locking of emitters in an extended cavity on their rear facet, and their coherent combination on the front facet. This rear-side technique provides strong optical feedback for phase-locking while maintaining a high electrical-to-optical efficiency. Two high-brightness high-power tapered laser diodes are coherently combined using a Michelson-based cavity – the combining efficiency is above 82% and results in an output power of 6.7 W in a nearly diffraction-limited beam with an M²4σ ≤ 1.2. A semi-active automatic adjustment of the current enhances the long-term stability of the combination, while the short-term stability is passively ensured by the extended cavity. This new laser configuration exhibits the simplicity of passive self-organizing architectures, while providing a power conversion efficiency of 27% that is comparable to master-oscillator power amplifier architectures.

Domains: Optics [physics.optics]; Optics / Photonic

Guillaume Schimmel, Ioana Doyen-Moldovan, Sylvie Janicot, Marc Hanna, Jonathan Decker, et al.. Rear-side resonator architecture for the passive coherent combining of high-brightness laser diodes. Optics Letters, 2016, 41 (5), pp.950-953. ⟨10.1364/OL.41.000950⟩. ⟨hal-01282939⟩