High-frequency beam steering in vertical-cavity surface-emitting lasers: optical gain and waveguiding effects

Static and dynamic characteristics of weakly index-guided vertical-cavity s urface-emitting lasers in a multi-transverse-mode regime are analyzed by us e of a model that takes into account the transverse modes supported by the waveguide and a consistent spectral gain including many-body effects. Waveg uide effects are addressed by consideration of different refractive-index s teps. We show that stronger competition between transverse modes occurs whe n their confinement in the waveguide is increased. Selection of a particula r high-order transverse mode by use of azimuthal-dependent current profilin g can be obtained over a wide current range. We study the alternate current modulation of two orthogonal high-order transverse modes, taking into acco unt thermal effects. This current-induced spatial switching leads to good-q uality high-frequency beam steering in the laser azimuthal direction when a n appropriate current profile is considered according to the refractive-ind ex step. (C) 1999 Optical Society of America [S0740-3224(99)01211-4].