Improving beam quality of diode laser array by wavelength beam combining

Based on the technology of wavelength beam combining, this paper applies the diffraction of the grating and the feedback of the external cavity to demonstrate all elements of the diode laser array(LDA) locked in different wavelength, the neighboring emitters having little difference in output wavelength. The output beam from the external cavity coupler mirror is nearly parallel, the combined beam has the same beam quality as the beam of single element of the LDA, but the brightness of the combined beam grows with the number of the LDA element. The 1 cm linear array was used in the experiment, consisting of 49 wide-aperture diodes with a diode width of 100 μm and a fill factor of 0.5. The combined beam power is 2.39 W, the wavelength spread is about 27 nm, the diameter of a circle spot is