Abstract:

To design an optical system for high power laser diodes, its far field distribution should be acquired exactly. Using the vector Rayleigh-Sommerfeld far-field diffraction integral formula, a vector model for describing the propagation of a high-power laser diode is proposed. Through the analysis of the properties of the TM-mode propagation, the expressions for the optical intensity and divergence angle are deduced, and the error is also analyzed compared with the scalar theory. It is found that the far-field intensity distribution and the divergence angle between the vector and scalar model are different. The error of intensity distribution is proportional to the coordinate perpendicular to the junction plane and inversely proportional to the propagation distance, and the difference of the divergence angle is related to the constants of the waveguide structure.

Key words: high-power laser diodes, Rayleigh-Sommerfeld diffraction, far-field intensity distribution, divergence angle