TRANSVERSE EFFECTS IN A LASER WITH AN INJECTED SIGNAL

We study the space-time behaviour of a single-longitudinal-mode laser in the presence of a small external signal, taking into account diffraction effects. Combining analytical and numerical results we show that for negative detunings there is a bifurcation from the trivial solution to a spatially homogeneous steady state, while for positive detunings a travelling wave is realized. In both cases, the solutions are superimposed on a spatially homogeneous oscillation at the frequency of the external field.