Dynamics of multimode semiconductor lasers

Abstract

We analyze multi-longitudinal-mode semiconductor lasers experimentally. We show that the intensity of each mode displays large amplitude oscillations but obeys a highly organized antiphase dynamics leading to an almost constant total intensity output. For each mode, regular switching is observed in the megahertz range, while the optical frequency as a function of time follows a well defined sequence from blue to red. Using a multimode theoretical model, we identify that four-wave mixing is the dominant mechanism at the origin of the observed dynamics. The asymmetry of the susceptibility function of semiconductor materials allows us to explain the optical frequency sequence.

Rate-equation model for multi-mode semiconductor lasers with spatial hole burning

“…The full electron-hole density in the active medium is expanded in a complete set of base functions, which allow for the introduction of inversion moments that not only describe the formation of gratings burned by the modal fields, but also provide the mechanism for mutual injection among the modal fields. Thus, we reproduce the Bogatov-effect on asymmetric side-mode suppression [7] and demonstrate the occurrence of a peculiar periodic multi-mode switching scenario similar to what has been reported and explained in [2] and [8]. We note that other nonlinear gain effects, such as carrier heating and two-photon absorption are neglected.…”

“…The multi-mode rate equations for the longitudinal modes of a semiconductor laser in this model are expressed in terms of ODEs for the complex modal field amplitudes, the overall population inversion and the various lasinginduced population-inversion gratings (spatial hole burning [4]), described by carrierinversion moments. This is a big advantage over existing models, which are based on complicated partial-differential and/or integral equations [1,2,5,6]. The model takes into account two interaction mechanisms among modes, i.e.…”

“…Moreover, the inclusion of spontaneous-emission noise in the modes and recombination noise in the carriers in such frame would be straightforward and could easily be carried through. In fact, in a multi-mode semiconductor diode laser several phenomena have their origin in the deterministic nonlinear dynamical evolution of the lasing modes [1,2].…”

Synchronization and Clustering in a Multimode Quantum Dot Laser

“…We observe that groups of modes may have the same frequency indicating the appearance of clustering. We also observe the propagation of perturbations across the optical spectrum from blue to red similar to those observed in quantum well semiconductor lasers [12]. Transient propagation of waves in the spectrum of a laser was previously observed in a fiber laser [13].…”

“…Clearly, this channel selection is not related to the linear gain distribution or other dispersion features neglected to derive the degenerate rate equations. This symmetry breaking was recently reported for multiple quantum well multimode semiconductor lasers [12]. Modeling is more advanced for those lasers and four-wavemixing together with a finite factor could be unambiguously assigned as the origin of this selective blue-to-red propagation mode.…”