High beam quality, high brightness dense spectral beam combining of 650 nm laser diode module

Dense spectral beam combining (DSBC) of a laser diode module at a wavelength of 650 nm was realized for what we believe to be the first time. In this paper, the optimal spectral locking interval range for the 650 nm wavelength band was obtained by stimulation. A DSBC device containing 19 single emitters was designed and built according to the optimal spectral interval. The output power of the combining beam reached 17.74 W, and the stable spectral width was 4.75 nm. The beam quality factors (M²) in the fast-axis and slow-axis directions were basically the same as that of the single emitter, and even slightly optimized in the slow-axis direction. The beam brightness of the DSBC beam was about 123.395 MW·cm^-2·sr^-1, which was about fourteen times higher than that of the single emitter output.