Optical switching in the semiconductor directional coupler with saturated gain

A detailed theoretical study of optical switching by gain saturation-induced phase shift in semiconductor directional couplers has been carried out by solving the electromagnetic equation for a spatially inhomogeneous refractive index distribution using the method of Yeh, Brown, and Szejn [Appl. Opt. 18, 489 (1979)]. The gain saturation-induced phase shift is calculated as a function of the antiguidance factor, injection current density, and input power. The results clearly show that the antiguidance factor and injection current density drastically affect the phase shift. However, the phase shift has only a weak dependence on the input power. In addition, it is also shown that the phase shift is proportional to the antiguidance factor and injection current density for a constant input power. Based on the results presented, the future of optical gain saturation-induced light switching in directional couplers should prove to be very promising.