Coherent combining in an Yb doped double core fiber laser

We have experimentally demonstrated coherent combining in an Yb doped double core fiber laser. More than 85% of the total output power is combined on the fundamental mode of one of the two cores. This efficient power combining is confirmed by the expected modulated spectrum of the emitted radiation. Finally, this combining method can be scaled with a good efficiency to a larger number of cores with a good efficiency leading to a high power single mode emission.