Joint time-frequency measurements of modelocked semiconductor diodelasers and dynamics using frequency-resolved optical gating

摘要

Joint time-frequency ultrafast measurements usingnfrequency-resolved optical gating (FROG) have been used to provide anfundamental understanding of: (1) ultrashort pulse propagation innsemiconductor optical amplifiers; (2) the modelocking dynamics innexternal cavity semiconductor diode lasers; and (3) correlatednmultiple-wavelength generation from mode locked semiconductor lasers.nThe pulse shaping and chirping effects measured by FROG are shown to benattributed to intracavity gain and saturable absorbing dynamics, as wellnas group velocity dispersion. In addition, the intracavity gain dynamicsnshow a regime of transient unsaturated gain, which can be exploited tonallow phase-correlated multiple-wavelength modelocked operation from ansingle-stripe external-cavity semiconductor diode laser. In this case,nFROG techniques are used to understand the underlying mechanismsninvolved in the phase correlation process