Spectral linewidth in oxide-confined vertical-cavitysurface-emitting lasers

摘要

We present a model to compute the linewidth in vertical-cavitynsurface-emitting lasers (VCSELs), by accounting for the 3-D structure ofnreal devices. To this aim, we include the noise source in the fieldnequations and treat both the noise and the structural characteristics bynmeans of coupled-mode theory. In this way, we obtain an expression fornthe linewidth that is given as the standard relation, modified by twoncorrection factors that account for spatial effects and modal dispersionnof the resonator. In the numerical results, we study for oxide-confinednVCSELs the transition from index to gain-guided regime, where thenstandard linewidth theory does not hold, and we give some guidelines fornnarrow-line emission devices