Study on beam characteristics of semiconductor laser based on Wigner distribution function

Semiconductor laser is partially coherent beam, while the beam quality factor is based on fully coherent beam. The Wigner distribution function for partially coherent beam is used to analyze the semiconductor laser beam. The Wigner distribution function contains both spatial information and spatial frequency information in the phase space. A method for measuring the Wigner distribution function of semiconductor laser is reported. The intensity distribution of the beam caustics is measured by two focusing mirrors, and the Wigner distribution function of semiconductor laser is reconstructed. Based on the reconstructed Wigner distribution function, the light intensity of semiconductor laser is simulated. The simulated data are in good agreement with the experimental data. Through the properties of Wigner distribution function, the wavefront aberration and coherence of semiconductor laser are analyzed. The wavefront of semiconductor laser is symmetrically distributed around a point, and the wavefront on the left side of the laser diode array is larger than that on the right side. Due to the temperature difference of the laser chip, the coherence on both sides of the laser diode array is better than that in the middle of the laser diode array.