Apparatus for providing optical radiation (10) comprising a pump array (8) for providing pump radiation (7), a first pump combiner (1), and a waveguide (3), wherein the pump radiation (7) from the pump array (8) is coupled into the waveguide (3) via the first pump combiner (1), and wherein the waveguide (3) comprises a pump guide (4) for guiding the pump radiation (7), and a gain medium (5) which emits the optical radiation (10) when it is pumped by the pump radiation (7).