Gain Dynamics after Ultrashort Pulse Trains in Quantum Dot based Semiconductor Optical Amplifiers

Influence of optical pumping wavelength on the ultrafast gain and phase recovery acceleration of quantum-dot semiconductor optical amplifiers

“…where the numbers of electrons (holes) in the QW, the jth group of the US, the jth group of the ES, and the jth group of the GS are n eg = 1 (0.13) ps, referring to the QD carrier relaxation times measured by ultrafast pump-probe experiments [4][5][6]. Because the QD active region is p-doped, the hole relaxation time is shorter than the electron relaxation time [19].…”

“…Quantum-dot (QD) semiconductor optical amplifiers (SOAs) have drawn great attention as high-speed, high-performance, and cost-effective optical amplifiers for linear amplification and all-optical wavelength conversion [1][2][3]. According to the ultrafast pump-probe measurement, the sub-picosecond gain recovery was observed in QD SOAs, which enables pattern-effect-free signal amplification up to hundreds of Gbit s −1 [4][5][6]. In contrast to the ultrafast gain recovery, the nanosecond phase recovery was shown to be limited by the slow carrier refilling of the carrier reservoir, which was determined by the spontaneous recombination rate [7].…”

Effect of wetting-layer density of states on the gain and phase recovery dynamics of quantum-dot semiconductor optical amplifiers

“…Due to high optical nonlinearities, QD SOAs are also the promising building blocks for all-optical signal processing either as a stand-alone element [5][6][7] or incorporated in interferometric configurations [8][9][10][11][12]. The sub-picosecond gain recovery time, supporting pattern-effect-free signal amplification up to hundreds of Gbit s −1 , was measured from the ultrafast pump-probe experiments in electrically-driven QD SOAs [13][14][15]. This ultrafast gain recovery time has never been achieved in quantum-well (QW) or bulk SOAs.…”