Abstract

We experimentally and numerically investigated the characteristics of polarization self-modulation in vertical-cavity surface-emitting lasers (VCSELs). Polarization self-modulation was induced by using feedback from an external reflector with a quarter-wave plate to rotate the polarization direction by 90° [1]. We obtained a switching frequency of 9.18 GHz. The time traces clearly showed that the square-wave output for long cavity lengths changed to sinusoidal output for short cavity lengths indicating that the modulation characteristics are determined by a fundamental decay time. We also found that the external cavity system for short cavity lengths assumes eigenstates that are different from the free-running VCSEL eigenstates.

© 1998 IEEE