Effect of crosstalk on spectrally combined beam properties and efficiency in external cavities

Considering the potential crosstalk in spectral beam combining systems, a theoretical model of spectrally combined beam properties and efficiency is proposed. This model is derived based on the diffraction integral method and the Lang–Kobayashi rate equations and is further used for deriving the analytical expressions of the combined beam intensity distribution and the combining efficiency. On this basis, the influence on the beam properties and combining efficiency of the crosstalk effect and the parameters of optical components is simulated and analyzed in detail. The results show that the crosstalk significantly affects the intensity distribution, combining efficiency, and beam quality, as well as the spectrum of the combined beam. A tradeoff between the reflectivities of the back facet of the diode laser array and the coupling mirror should be made to optimize the combining efficiency and the spectrum stability.