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A fiber side-pump combiner is presented. This pump combiner does not interrupt the core of the active fiber, thus allowing for monolithic fiber lasers and amplifiers. Using one of these devices, the power coming from seven pump diodes was combined and a maximum of 86 W was coupled in an active fiber. An similar to 30 W laser using this side-pumping concept was also demonstrated

We report on an integrated all-glass pump combiner for ytterbium-doped high power fiber lasers. The combining of multiple pump fibers with an active double clad fiber for high power amplification was successfully achieved by splicing them to a dichromatically coated planar convex lens. The measured coupling efficiency of such a combining scheme was typically in excess of 80%, with 86.5% achieved in maximum. Theoretical analysis is discussed in order to get optimized parameters and to consider the scaling of this type of coupler to higher average powers.

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We present an all-fiber side pump combiner for high power fiber lasers and amplifiers. It consists of a capillary with decreasing wall thickness fused around the active fiber in a way that it becomes an additional cladding layer of it. The pump fibers are spliced at the edge of the capillary with the thickest wall. This provides enough room to allocate around 12 pump fibers (100µm diameter) in a standard 400µm double-clad fiber. This side pump combiner offers several advantages such as the fact that it does not interrupt the active fiber core at any point, thus allowing for truly monolithic all fiber lasers and amplifiers. Additionally, the pump light is coupled into the active double-clad fiber all along the combiner's body (~ 1-2 cm long), which avoids the concentration of heat in a very small area, resulting in high pump power handling capabilities. If the taper angle of the capillary wall is low enough a high coupling efficiency (< 95%) is possible. Using this structure we have achieved a maximum combined pump power of 86 Watt from 7 pump diodes. This, we believe, is the highest combined pump power reported so far from a single lumped side pump combiner