  The correct accounting for thermal effects is always a challenge when one
needs to make quantitative predictions for any laser applications. In such
complicated devices as quantum cascade lasers temperature strongly affects the
operational conditions preventing reaching the CW mode as well as efficient
lasing in pulsed regime. Rate equations are the most effective and simple way
to model laser dynamics. However, the conventional approaches operate under the
mean-field approximation, considering finite number of population levels,
generalizing the obtained results to the infinite number of cascades, and do
not take heating into account. In this work we modify the conventional
three-level rate equation approach by adding self-heating description and
applying it to the calculation of QCL dynamics. As a result we show how
temperature affects the threshold characteristics and build-up time and include
electronic aspects to the description of QCL.
