High beam quality in two directions and high efficiency output of a diode laser array by spectral-beam-combining

Improvement is made in the traditional spectral beam combining structure by adding beam shaping element, namely Beam Transformation System (BTS). Spectral beam combination is performed in a horizontal direction by the external cavity after beam shaping. The effect of smile and the divergence of the slow axis are reduced. A standard semiconductor laser array is used in this experiment. A CW output power of 58.8 W and an electro-optic conversion efficiency of 51% are achieved. The spectral line-width is 12.7 nm. M(2) of 1.3 × 11.6 in horizontal and vertical directions are obtained. The beam quality of the output is close to that of a single emitter of the array in two directions.