Contents Introduction
Long-wavelength semiconductor lasers with Fabry-Perot (FP) cavities show broad spectra at high-injection levels. Mode coupling of longitudinal modes has been studied. Tiemeijer et al. reported passive FM-mode locking of InGaAsP lasers by measuring second harmonic generation (SHG) spectra [1]. Recently, we reported optical pulse generation using an FP laser [2]. The laser output was compressed via fiber dispersion. In this paper, passive mode locking of FP lasers is investigated experimentally. Mode-locking instability appearing as frequency jumps at different currents is described.
