Index and gain dynamics of optically-pumped GaInNAs vertical-cavity semiconductor optical amplifiers

To study the dynamic effects in GaInNAs vertical-cavity semiconductor amplifiers (VCSOAs), we carried out a pump-probe experiment on an optically biased VCSOA, first at antiresonance and then in gain. At antiresonance, the highest absorption region of the amplifier, the carrier-population-depletion-induced shift in the wavelength of the absorption was measured as a function of pump-probe delay. The corresponding index recovery time was measured to be ~50 ps±5 ps. In the amplification regime, we observed that the carrier depletion induced by the pump pulse decreased the available gain. The recovery time for the device gain in dB under these conditions was measured at ~55±15 ps. These results indicate that GaInNAs VCSOAs can process data at 10 Gbits/s with no patterning effect.