Coherent combining in an Yb doped double core fiber laser

International audienceCoherent combining is demonstrated in a clad pumped Yb doped double core fiber laser. A slope efficiency of more than 70 % is achieved with 96 % of the total output power on the fundamental mode of one of the two cores. This high combining efficiency is obtained when both cores are coupled via a biconical fused taper in a Michelson interferometer configuration

Tunable red-light source by frequency mixing from dual band Er/Yb co-doped fiber laser

International audienceWe report an all solid state laser device producing tunable dual wavelength emission in the near IR region (1060nm, and 1550 nm) by use of an Er/Yb co-doped fiber. Generation of continuous-wave radiation around 630 nm is then demonstrated by extra-cavity sum frequency mixing in a Periodically Poled Lithium Niobate (PPLN) crystal. Quasi phase matching conditions are obtained over 7 nm to generate tunable coherent light in the red spectral range

Coherent beam combining with an ultrafast multicore Yb-doped fiber amplifier

International audienceActive coherent beam combination using a 7-non-coupled core,polarization maintaining, air-clad, Yb-doped fiber is demonstrated as amonolithic and compact power-scaling concept for ultrafast fiber lasers. Amicrolens array matched to the multicore fiber and an active phasecontroller composed of a spatial light modulator applying a stochasticparallel gradient descent algorithm are utilized to perform coherentcombining in the tiled aperture geometry. The mitigation of nonlineareffects at a pulse energy of 8.9 μJ and duration of 860 fs is experimentallyverified at a repetition rate of 100 kHz. The experimental combiningefficiency results in a far field central lobe carrying 49% of the total power,compared to an ideal value of 76%. This efficiency is primarily limited bygroup delay differences between cores which is identified as the maindrawback of the system. Minimizing these group delay issues, e.g. by usingshort and straight rod-type multicore fibers, should allow a practical powerscaling solution for femtosecond fiber systems

Nanosecond OPO energy features improvement by spatio-temporal shaping of the pump beam

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Intracavity coherent shaping of laser beams

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Self-organized fiber beam combining

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Temporal laser beam construction under controlled mode filtering

International audienceThe transient regime of a new type of free-running Nd: YAG laser including two spatial filters in order to synthesize an unusual transverse mode is studied. The laser is seeded by a short (30 ps) laser pulse, and a streak camera analyses the transverse beam profile after each cavity round-trip. The expected filtered mode is obtained after approximately 15 round-trips. This result shows the ability of this original filtering to be used by others emission regimes and gain mediums