Stability properties of the monochromatic spectrum in a double-cavity laser

We discuss the process by which the spectrum of monochromatic modes of the laser in a double-cavity laser changes from that proper to a shea cavity in to that proper to a long cavity as the reflectivity of the "external'' mirr or is varied from 0 to 1. This work is the natural continuation of our prev ious work [Phys. Rev. A 58, 614 (1998)], where the bifurcations occurring d uring this metamorphosis were studied. The transformation is mostly dictate d by the boundary conditions and occurs regardless of the laser model. This transition is beyond the possibilities of simpler double-cavity laser mode ls, such as those of Lang and Kobayashi [IEEE J. Quantum Electron. QE-16, 3 47 (1980)]. The stability properties of the monochromatic modes are studied as a function of the reflectivity of the external mirror R, the external c avity length L, and the applied current J. It is shown that for reflectivit y values corresponding to the metamorphosis of the spectrum, by varying J a nd/or R, the system can give rise to a Hopf instability that involves the e xcitation of a roughly discrete set of frequencies. Note that these feature s are also beyond the possibilities of simpler models. We also discuss the role played by noise and show that it is possible for the system to show a high degree of susceptibility to noise, depending on J. [S1050-2947(99)1060 8-5].