FAR-FIELD AND BEAM CHARACTERISTICS OF VERTICAL-CAVITY SURFACE-EMITTING LASERS

We have determined the far-field patterns and beam parameters of verti cal-cavity surface-emitting lasers (VCSELs) with different structures. The results show that the window diameter and the active-layer apertu re of VCSELs strongly influence laser far-field distributions and beam characteristics; for VCSELs with small window omega=5 mu m, only one dominant lobe has been observed in the far-field profiles, even though injected current was increased up to 2 Ith; and the smaller the ratio of the window diameter to the active-layer aperture, the larger is th e far-field divergence. The laser structure dependence of the K factor has also been studied. (C) 1996 American Institute of Physics.