Output power characteristics and efficiency of novel surface‐emitting superluminescent diodes are presented. Tilted micromirrors terminate an in‐plane waveguide, and laterally gain‐guided modes are deflected perpendicularly to the anti‐reflection‐coated chip surface. The epitaxial structures are grown by a metal‐organic vapor‐phase epitaxy with several InGaAs/GaAs quantum wells emitting at a peak wavelength of 950 nm, and the chip technology involves only wafer‐scale processes. The spectral full width at half maximum of the amplified spontaneous emission is larger than 10 nm. In a pulsed operation, a room temperature output power that exceeds 250 mW with a wall‐plug efficiency higher than 15% is achieved.