Fiber-coupling technique with micro step-mirrors for high-power diode laser bars

A technique for coupling the output of a high-power diode laser bar into one multimode fiber with high efficiency, easy alignment requirements and low manufacturing costs is demonstrated using a single fiber with 400 μm core diameter. This technique comprises two micro step-mirrors for beam shaping. The overall efficiency from diode-laser to fiber is 71% with 20 W cw laser power through the fiber.