Polarization properties of vertical-cavity surface-emitting lasers

Abstract

Polarization-state selection, polarization-state dynamics, and polarization switching of a quantum-well verticalcavity surface-emitting laser (VCSEL) for the lowest order transverse spatial mode of the laser is explored using a recently developed model that incorporates material birefringence, the saturable dispersion characteristic of semiconductor physics, and the sensitivity of the transitions in the material to the vector character of the electric field amplitude. Three features contribute to the observed linearly polarized states of emission: linear birefringence, linear gain or loss anisotropies, and an intermediate relaxation rate for imbalances in the populations of the magnetic sublevels. In the absence of either birefringence or saturable dispersion, the gain or loss anisotropies dictate stability for the linearly polarized mode with higher net gain; hence, switching is only possible if the relative strength of the net gain for the two modes is reversed. When birefringence and saturable dispersion are both present, there are possibilities of bistability, monostrability, and dynamical instability, including switching by destabilization of the mode with the higher gain to loss ratio in favor of the weaker mode. We compare our analytical and numerical results with recent experimental results on bistability and switchings caused by changes in the injection current and changes in the intensity of an injected optical signal.

Deterministic polarization chaos from a laser diode

“…These polarization characteristics call for an interpretation that is different from a stochastic Kramers hopping problem applied to symmetric bistable states, as is typically done for VCSELs 34 .Our experiment can qualitatively be reproduced well using the San Miguel, Feng and Moloney (SFM) model. The model considers two competing emission processes for the right and left circular polarization with two coupled carrier reservoirs 20,36 ; the coupling comes from multiple complex spin-flip processes, i.e. sub-picosecond mechanisms that contribute to the relaxation of electron spin (see e.g.…”

“…To do so we make direct numerical integrations of the SFM model using the following parameters (notations are identical to the one used by Martin-Regalado et al 36 ): amplitude anisotropy  a = −0.7 ns -1 , phase anisotropy  p = 4 ns -1 , linewidth enhancement factor  = 3, spinflip processes decay rate  s = 100 ns -1 , decay rate of the electric field in the cavity  = 600 ns -1 , decay rate of the total carrier number  = 1 ns -1 and normalized injection current  in [1,10]. We use a classic 4-stage Runge Kutta algorithm with a time step of 1 ps.…”

Polarization squeezing in vertical-cavity surface-emitting lasers

“…The stability analysis of these stationary solutions was performed in a number of publications, as for example, Refs. [16,17], and we refer the reader to this papers for details. In our analysis of quantum fluctuations we shall assume that the corresponding stationary operation regime of VCSEL is stable.…”

“…(2.7). Moreover, we shall define the fluctuations of the amplitude and the phase quadrature components, δX x (t) and δY x (t) of the x-polarized field component, 16) and similar for the y-polarized component. For these fluctuations we obtain the following equations, 18) where the new Langevin forces R x (t) and S x (t) are defined as…”

Square-wave switching in vertical-cavity surface-emitting lasers with polarization-rotated optical feedback: Experiments and simulations

“…The spin-flip model equations [25], extended as in Refs. [11,17] to account for polarization-rotated time-delayed feedback, are:…”