Enhanced Polarization Locking in VCSELs
This addresses a bottleneck in enabling polarization-encoded computing with VCSELs, though it is incremental as it builds on existing optical injection locking methods.
The paper tackled the limited polarization switchability of VCSELs for applications like polarization-encoded Ising computers by fabricating devices with tailored oxide apertures and using bias current tuning, resulting in reduced injection power to as low as 3.6 μW and an expanded locking range.
While optical injection locking (OIL) of vertical-cavity surface-emitting lasers (VCSELs) has been widely studied in the past, the polarization dynamics of OIL have received far less attention. Recent studies suggest that polarization locking via OIL could enable novel computational applications such as polarization-encoded Ising computers. However, the inherent polarization preference and limited polarization switchability of VCSELs hinder their use for such purposes. To address these challenges, we fabricate VCSELs with tailored oxide aperture designs and combine these with bias current tuning to study the overall impact on polarization locking. Experimental results demonstrate that this approach reduces the required injection power (to as low as 3.6 μW) and expands the locking range. To investigate the impact of the approach, the spin-flip model (SFM) is used to analyze the effects of amplitude anisotropy and bias current on polarization locking, demonstrating strong coherence with experimental results.