Saturation Power of a Semiconductor Optical Amplifier Based on Self-Organized Quantum Dots

Gain saturation in a semiconductor optical amplifier with an array of quantum dots is studied analytically and by numerical simulation on the basis of an analysis of rate equations. It is shown that, at a moderate injection level, the saturation power increases in proportion to the current density, and then reaches its maximum value, limited by the rate of carrier delivery to the ground state and by the number of quantum dots interacting with photons. Expressions are proposed that allow explicit description of the dependence of the saturation power on current and its relationship with the internal parameters of the active region.