Spatiotemporal dynamics and high-frequency self-pulsations in two-section distributed feedback lasers

Ne present a traveling-wave large-signal simulation of the spatiotemporal dynamics of two-section distributed feedback lasers, emphasizing the self-pulsation phenomenon. For index-coupled lasers, self-pulsation is a result of the interaction of two modes, each spatially confined primarily to one section. For partially gain-coupled lasers, self-pulsation is a result of the interaction of two modes, one that is spatially confined primarily to one section and another that belongs to both sections. The self-pulsation frequency-tuning range and the modulation index of partially gain-coupled lasers are found to be substantially larger than those of index-coupled lasers. Experimentally, self-pulsation with a frequency-tuning range from 20 to 60 GHz in two-section partially gain-coupled distributed-feedback; lasers has been characterized in the electrical domain. The noise of self-pulsation was reduced experimentally by optical feedback. (C) 1999 Optical Society of America [S0740-3224(99)01811-1].