Improvement of Gain Recovery in QD-VCSOA at 1-Tb/s Cross Gain Modulation Using an Additional Light Beam

The acceleration of gain recovery in quantum dot vertical cavity semiconductor optical amplifiers (QD-VCSOA) is investigated. The 1-Tb/s pattern effect free cross gain modulation in QD-VCSOA can be achieved by using an additional light beam. We can overcome the limitation of the slow transition of carriers from the wetting layer to the excited state by applying a light beam which increases the carrier density in the excited state and thus strongly improves the gain recovery time.