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We study experimentally the role of the bias current sweep rate in measurements of polarization switching ͑PS͒ of vertical-cavity surface-emitting lasers. We find that the size of the hysteresis cycle of the PS for increasing and decreasing current follows a power-law relationship with the speed of the current ramp. A similar relation is found for the laser turn-on. Numerical calculations based on the spin-flip model are in good agreement with the observations. We also show that the PS points and the power-law exponents depend critically on the noise level included in the simulations.

We study the role of the bias current sweep rate in measurements of polarization switching (PS) of vertical-cavity surface-emitting lasers (VCSELs). We show that the polarization-resolved L-I (light-intensity) curve depends on the current sweep rate. As the current sweep rate increases, the PS occurs at higher bias currents for upward scans and at lower bias currents for downward scans. We also show that the delay of the dynamical bifurcation follows a power law relationship with the frequency of the ramp, in good agreement with recent theoretical predictions.

We study experimentally and numerically the influence of orthogonal optical feedback on the polarizationresolved light versus bias current characteristic (L-I curve) of vertical-cavity surface-emitting lasers (VC-SELs). The feedback scheme is such that only one linear polarization is selected to be fed back into the laser while the orthogonal polarization is completely suppressed before the output is rotated 90°and reinjected into the laser. We experimentally demonstrate that weak feedback levels modify the polarization switching point only slightly, but as the feedback increases the otherwise depressed mode grows and the hysteresis is suppressed. While polarization-preserved and X-orthogonal feedback have similar effects (X indicates the direction of the polarization selected at threshold), Y-orthogonal feedback strongly modifies the shape of the L-I curve, even suppressing the polarization-switching for strong enough feedback. Numerical simulations of the spin-flip model show good qualitative agreement with the observations. We also analyze the influence of various parameters, such as linear birefringence, dichroism, and the spin-flip relaxation rate.

An experimental demonstration of the effect of chaos pass filtering on high-frequency message transmission in the complete synchronization regime is reported. The opportunity for chaotic message decoding at frequencies up to 6 GHz is shown.