Enhanced Polarization Locking in VCSELs

TL;DR

This paper enhances polarization locking in VCSELs by tailored design and bias tuning, reducing power needs and expanding locking range, supported by experimental and theoretical analysis.

Contribution

It introduces a novel VCSEL design and bias tuning method to improve polarization locking, enabling potential computational applications.

Findings

Reduced injection power to as low as 3.6 μW.

Expanded polarization locking range.

Strong agreement between experimental results and spin-flip model analysis.

Abstract

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 {\mu}W) 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.