Broadband Polarization Chaos in Optically Pumped QD spin-VCSELs under Optical Injection for Ultrafast Random Bit Generation

The present contribution provides a link between optical pumping with polarized light and polarized optical injection in a Quantum-Dot (QD) Vertical-Cavity Surface-Emitting Lasers (VCSEL). Based on the sensitivity of the QD spin-VCSEL to the stability state before the injection and the rich dynamic behaviour induced by optical injection we perform an analysis of optimized parameters for the demonstration of extended chaotic regions. The proposed scheme aims at ultrafast random bit generation (RBG) reducing the complexity of well-established systems based on VCSELs to generate high-quality chaos signals. Our investigations reveal that inside these regions an enhancement of chaotic bandwidth up to 50 GHz can be achieved, exceeding the state-of-the-art performance of conventional VCSELs under continuous wave (CW) optical injection. We show that in addition to exhibiting enhanced polarization chaos, QD spin-VCSELs enable 240 Gbit/s RBG thus allowing future exciting routes for cryptography and secure communications.