Simulation on intensity self-pulsation in cw semiconductor lasers

Intensity self-pulsation in cw semiconductor lasers has been analyzed by computer simulation assuming saturable absorbing characteristics in the loss term of the rate equation. A loss decrease of about 1% due to the saturable absorber is capable of generating self-pulsation. The theoretical pumping dependence of the self-pulsation frequency is consistent with the experimental data. Reflected light in the range of 10⁻⁵∼10⁻³ reduces the self-pulsation. Reflected light of larger than 10⁻², however, induces self pulsation whose frequency is locked with the round trip time. The contribution of spontaneous emission in the range of 10⁻⁴∼10⁻³ also reduces the self-pulsation, while 10⁻⁶∼10⁻⁵ is ineffective.