In this paper the injection locking properties of two laterally-coupled semiconductor lasers (LCSLs) are studied numerically. We consider external injection into either one (single external-injection scheme) or both (simultaneous external-injection scheme) of the LCSLs. We present stability maps for both schemes in the plane of the frequency detuning and the injection strength, where attention is centered on the influence of the waveguiding structures, the laser separation, the pump rate, and the frequency offset between the two coupled lasers. Our results contribute to a better understanding of LCSLs under external injection.
Spin-polarized vertical (external) cavity surface-emitting lasers [Spin-V(E)CSELs] using quantum dot (QD) material for the active region, can display polarization switching between the right- and left-circularly polarized fields via control of the pump polarization. In particular, our previous experimental results have shown that the output polarization ellipticity of the spin-V(E)CSEL emission can exhibit either the same handedness as that of the pump polarization or the opposite, depending on the experimental operating conditions. In this contribution, we use a modified version of the spin-flip model in conjunction with combined time-independent stability analysis and direct time integration. With two representative sets of parameters our simulation results show good agreement with experimental observations. In addition periodic oscillations provide further insight into the dynamic properties of spin-V(E)CSELs.
Random bit generation (RBG) with chaotic semiconductor lasers has been extensively studied because of its potential applications in secure communications and high-speed numerical simulations. Researchers in this field have mainly focused on the improvement of the generation rate and the compactness of the random bit generators. In this paper, we experimentally demonstrate the existence of two regimes of fast RBG using a single chaotic laser subjected to delayed optical feedback: the first one is based on the extraction of all min-entropy contained in each random sample, and the second one is to demonstrate a possibility of increasing the generation rate by extracting 55 bits from each variable.
We report experimental bifurcation diagrams (BDs) of an external-cavity semiconductor laser (ECSL). We have focused on the case of the ECSL biased just above threshold to moderate and subjected to feedback from a distant reflector and observed a sequence of bifurcations involving bifurcation cascade as well as intermittency between multiple coexisting attractors. More importantly, we reiterate: the results map out, for the first time to our knowledge, detailed BDs of the ECSL as a function of feedback strength for various external cavity lengths and currents, thus covering a significant portion of parameter space. We have grounded our discussion in extensive theoretical studies based on the Lang-Kobayashi equations and simulated BDs in accordance with our experimental results.