Nonlinear gain suppression in quantum-well lasers due to carrier heating: the roles of carrier energy relaxation, electron-hole interaction, and Auger effect

The influences of carrier energy relaxation and electron-hole interaction on the nonlinear gain coefficient are detailed inspected by a numerical comparison of carrier heating model with classical rate-equation model in a large-signal analysis. It is shown that the nonlinear gain coefficient due to carrier heating is in proportion to an effective carrier energy relaxation time and has a nonlinear relation to the electron-hole energy exchange time. Accordingly, an empirical formula is deduced. In addition, the influence of Auger heating on the modulation dynamics is also considered, which can not be described by a single phenomenological nonlinear gain coefficient. Furthermore, the dependence of the nonlinear gain coefficient on the laser emission wavelength of distributed feedback laser is also demonstrated quantitatively.