Theory of second-order mode locking in semiconductor lasers

Due to the high dispersion near the band gap, normal mode locking cannot occur in usual semiconductor lasers. According to the Paoli-Ripper model the pulse properties of such lasers can be explained in terms of second-order mode locking. We present an analytical quantitative treatment of the Paoli-Ripper model and apply the results to the GaAs laser diode. A rather good agreement between theory and experiment is achieved.