Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 63: Devices I

HL 63.5: Talk

Wednesday, March 28, 2012, 16:00–16:15, EW 015

Two-color pump-probe experiments with balanced heterodyne detection on InAs/GaAs quantum dot semiconductor optical amplifiers — •Yücel I. Kaptan, Nina Owschimikow, and Ulrike Woggon — Technische Universität Berlin, Institut für Optik und Atomare Physik, Berlin, Germany

Degenerate one-color pump-probe measurements combined with a balanced heterodyne detection scheme prevailed in the last decade as a leading experimental tool for the measurement of gain and phase dynamics in QD SOAs. In this talk, we present an improved two-color pump-probe setup in which a mode-locked Ti:Sa laser and an infrared super continuum emitting fiber laser provide independently tunable ultrafast pump and probe pulses. Both laser sources have been synchronized via a phase-locked loop using a proportional-integral-derivative controller driving a piezo crystal. With a synchronization jitter of about 400fs we were able to investigate the carrier transition times between the QD ground and excited state, the 2D carrier reservoir and the waveguide. Separating the recovery within the QD states from the carrier recovery in the reservoir, we identify the carrier dynamics in the reservoir as the main contribution to overall phase dynamics and thus change in refractive index. We additionally show that the presented results of the intradot gain dynamics indicate a novel way for ultrafast switching of amplification and wavelength conversion.