Gain and Phase Recovery Dynamics in Quantum-Dot Vertical-Cavity Semiconductor Optical Amplifiers

In this paper, we present a numerical study of gain and phase recovery dynamics in InGaAs/GaAs quantum-dot (QD)-based vertical-cavity semiconductor optical amplifier (SOA) including effects of inhomogeneous broadening and bias currents. It is shown that the effect of inhomogeneous broadening on the gain and phase recovery time is not considerable. The results reveal that the values of the phase change as well as linewidth enhancement factor (LEF) are very small compared to traveling wave QD SOAs due to small length of cavity. Also, in low bias current, incomplete gain and phase recovery and small LEF are observed. For currents greater than 5 mA, the required current for complete ground state filling in P_in = 0 dBm, the complete recovery is calculated. It is shown that with further increasing of current, recovery time reduces while the final LEF value is unchanged.