Polarization switching and injection locking in vertical-cavity surface-emitting lasers subject to parallel optical injection

Abstract

Polarization switching in a long-wavelength vertical-cavity surface-emitting laser (VCSEL) under parallel optical injection is analyzed in a theoretical and experimental way. For the first time, to our knowledge, we report experimentally a state in which injection locking of the parallel polarization and excitation of the free-running orthogonal polarization of the VCSEL are simultaneously obtained. We obtain very simple analytical expressions that describe both linear polarizations. We show that the power of both linear polarizations depend linearly on the injected power in such a way that the total power emitted by the VCSEL is constant. We perform a linear stability analysis of this solution to characterize the region of parameters in which it can be observed. Our measurements qualitatively confirm the previous theoretical predictions.

1/ f noise in the intensity fluctuations of vertical-cavity surface-emitting lasers subject to parallel optical injection

“…Our experiment of hopping involves two states: one is a periodic dynamics (P1), similar to that illustrated in Figs. 2(a) and 2(b) of [7], while the other is a recently found state (IL+PS) [4], similar to the state shown in Figs. 2(e) and 2(f) of [7], that is a fixed point.…”

“…The second state occurs when the orthogonal polarization mode is activated [polarization switching (PS)] and the VCSEL locks its frequency to that of the injection laser [injection locking (IL)]. Usually only one of these phenomena occurs, but in a recent work [4] using parallel optical injection, a new state in which both phenomena (IL+PS) occur simultaneously was experimentally observed and theoretically analyzed. In IL+PS, injection locking of the parallel polarization and excitation of the free-running orthogonal polarization are simultaneously observed.…”

Analysis of the polarization of single-mode vertical-cavity surface-emitting lasers subject to parallel optical injection

“…This has been usually obtained for the case of orthogonal optical injection: linearly polarized light from an external laser is injected orthogonally to the linear polarization of the solitary VCSEL. Very recently it has been shown experimentally and theoretically that PS in single-transverse mode VCSELs can also be obtained for parallel optical injection, that is, the directions of linear polarization of the injected light and the free-running device are parallel [19]. A state, termed as IL+PS, in which injection locked emission in the parallel polarization and excitation of the free-running orthogonal polarization of the VCSEL occurs simultaneously was described.…”

“…A state, termed as IL+PS, in which injection locked emission in the parallel polarization and excitation of the free-running orthogonal polarization of the VCSEL occurs simultaneously was described. This is an unusual situation because optical injection in the polarization with smaller optical losses causes emission in the polarization with larger losses [19]. Very recently a linear stability analysis of the mixed-mode steady states of an optically injected twopolarization modes edge-emitting semiconductor laser has been performed [20].…”

“…Very recently a linear stability analysis of the mixed-mode steady states of an optically injected twopolarization modes edge-emitting semiconductor laser has been performed [20]. Dynamical evolution of mixed-mode steady states and IL+PS states is similar for VCSELs for which the spin dynamics can be adiabatically eliminated [19], and so the linear stability analysis of [20] was successfully extended to the VCSEL case [19]. Also two-mode equilibrium state (TME) has been observed in optically injected two-mode lasers [21][22][23].…”