The macroscopic behavior of a semiconductor laser medium is described by use of modified rate equations. The model, valid on time scales greater than 10 Ϫ13 s, explicitly treats carrier temperature as a dynamic variable and includes the nonlinear dependence of the gain function on carrier density and temperature. Gain suppression that is due to carrier heating is a natural consequence of the model and gives a qualitative explanation of subpicosecond gain dynamics experiments without introducing gain nonlinearity phenomenologically. We demonstrate the temperature behavior of the laser during transient dynamics near and well above threshold. By including carrier temperature as a dynamic variable we show that the laser response to an external perturbation exhibits a noticeable change in the damped oscillations of the photon density compared with that in models without temperature dynamics. Variation in the evolution of the gain function for different external pulse energies is also demonstrated.

The gain and carrier temperature response of semiconductor laser media to picosecond optical pulses with various pulse energies is obtained by means of a model that is based on rate equations extended to include the carrier energy density equation. The temperature dynamics are obtained from the carrier energy density by use of a quasi-equilibrium Fermi-Dirac distribution. We study the cases of media whose prepulse states are strongly absorbing, transparent, and strongly amplifying at the frequency of the pulse. The results show that the various physical processes that influence the gain and carrier temperature contribute differently, depending on both the initial state of the medium and the pulse energy. In particular, the influence of free-carrier absorption and two-photon absorption on the dynamics of the carrier temperature and the gain coefficient is discussed in detail.

To date, various connection rerouting methods for connection-oriented mobile networks have been proposed. The previous methods, however, are limited to specific topologies or environments. In this paper, we propose the connection-information-based rerouting widely applicable to various connection-oriented mobile networks. This method requires neither a specific topology nor a complex connection, enables fast rerouting, provides appropriate route optimality, and can be extended easily.

We explore the dynamic behavior of a monovelocity atomic beam. The equations describing the monovelocity atomic beam are similar to the Maxwell-Bloch equations. The steady-state, linear stability analysis, and dynamics verify that hysteresis, bistability, and even multistability of the output intensity exist in this system. Comparison of the loss–gain bifurcation curve of this system to the original maser model shows that the instability asymptote for the monovelocity atomic beam is κ = 0 where κ represents the loss parameter while the maser model asymptotes at κ > 1.