Zeghuzi, A.Schmeckebier, HolgerStubenrauch, M.Meuer, C.Schubert, C.Bunge, C.-A.Bimberg, Dieter2020-05-222020-05-2220150003-6951https://depositonce.tu-berlin.de/handle/11303/11200http://dx.doi.org/10.14279/depositonce-10088This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 106, 213501 (2015) and may be found at https://doi.org/10.1063/1.4921785.Error-free generation of 25-Gbit/s differential phase-shift keying (DPSK) signals via direct modulation of InAs quantum-dot (QD) based semiconductor optical amplifiers (SOAs) is experimentally demonstrated with an input power level of −5 dBm. The QD SOAs emit in the 1.3-μm wavelength range and provide a small-signal fiber-to-fiber gain of 8 dB. Furthermore, error-free DPSK modulation is achieved for constant optical input power levels from 3 dBm down to only −11 dBm for a bit rate of 20 Gbit/s. Direct phase modulation of QD SOAs via current changes is thus demonstrated to be much faster than direct gain modulation.en530 Physikquantum dotsoptical propertiesdata processingquantum wellssemiconductor optical amplifierssemiconductor lasersamplified spontaneous emissionelectrical properties and parametersamplitude modulationoptical communicationsArticle1077-3118