Incoherent laser beam combining based on signal combiners is an effective method to significantly increase the laser power. Although many high power signal combiners have been reported, most of these combiners have seven or less input ports. In this paper, a 19×1 signal combiner is fabricated based on tapered fiber bundle technique including optical fibers bundling with capillary, fiber bundle tapering, cutting, and fusion splicing to the output fiber. The input fibers of the combiner are 14/250 μm-core/cladding optical fibers, and the output fiber is a 100 μm-diameter-core multimode fiber. The signal combiner is tested with eight 1500 W fiber laser modules, and 11.55 kW output power is obtained. The beam parameter product is 3.83 under 2 kW laser output. The temperature rise of the signal combiner is measured under passive heat dissipation condition at different laser power outputs, and the thermal slope is calculated to be 1.56 °C/kW. This 19×1 combiner has the potential to be used in a 30kW-level or even higher power fiber laser system.
|