We consider a cylindrical vertical cavity surface-emitting laser with a square-shaped active region, operating with the two Gauss-Hermite modes TEM10 and TEM01. Using a rate-equation model that includes the effects of the linewidth enhancement factor, we identify in the parameter space two bistability domains. The two stable states are in one case the doughnut modes and in the other the modes TEM10 and TEM01. Focusing on the latter case, we study numerically the conditions for optical switching from one mode to the other on injection of an appropriate control beam, and we demonstrate the possibility of using the laser as a NOR logic gate.
© 1994 Optical Society of America
F. Prati, M. Travagnin, and L. A. Lugiato, "Optical switching and logic gates with vertical cavity surface-emitting lasers," Opt. Lett. 19, 1991-1993 (1994)