Simulation of spectrally beam combined diode laser based on grating-cavity

The efficiency of spectral beam combining based on grating-cavity mostly depends on the coupling efficiency between emitter and cavity. Based on the diffraction integral equation, the coupling efficiency model with abaxial aberration is established. Then, the effect of the system parameters on the coupling efficiency is analyzed quantitatively. The results show that the coupling efficiency decreases when abaxial distance or the order of mode increases, or when mode field radius increases, or when the grating plane or the array plane deviates farther from the focal plane. The grating’s tilt angle and the distance between the grating plane and the output coupling mirror have few influence on the coupling efficiency. For the system with bi-convex lens of 500 mm focal length and 10 mm array