Nonlinear Dynamics in Semiconductor Lasers 2023 - Abstract
Lindemann, Markus
Fast intensity modulated diode lasers reach their fundamental limits for the modulation bandwidth in the regime below 50 GHz and thus represent a major contribution to the bandwidth bottleneck in optical data centers. Spin-controlled vertical-cavity surface-emitting lasers (Spin-VCSELs), in contrast, have been shown to enable modulation bandwidths exceeding 200 GHz because they operate with a different physical mechanism, based on the interplay of spin polarized electrons and the polarization of the light field in specifically anisotropic VCSEL cavities. Theoretical studies on the basis of a modified spin-flip model have shown that polarization modulation frequencies far above 200 GHz are feasible. So far, no physical limits have been identified, yet, that generally inhibit modulation frequencies approaching the THz range. Furthermore, the extremely high modulation bandwidth can be achieved even close to threshold in contrast to conventional intensity modulation where highest bandwidth is obtained far above threshold. Thus, spin-VCSELs are potentially much more energy efficient than intensity modulated lasers. We discuss the principle and the potential of spin-VCSELs for ultrafast modulation and develop a device architecture for room-temperature electrically pumped spin-VCSELs.