Self-pulsation within 650 nm, AlGaInP laser diodes can be achieved via the use of a saturable absorbing, epitaxial layer within the structure. A rate equation model of this type of device is presented, which includes the process of thermally activated charge transfer from the quantum well and gain region to the absorbing layer. The results indicate that this thermal leakage mechanism saturates the absorber and hence destroys the self-pulsation at high temperatures. Comparison of the model with recently published experimental data shows good agreement and provides a consistent explanation for the loss of pulsation at temperatures in excess of 60 °C. ©1997 American Institute of Physics.