Abstract

VCSELs can emit light in two states with orthogonal polarisations and switching between these polarisation states has been observed. Such Polarisation Switching (PS) can occur driven by current (with a bistable region), or driven by noise due to spontaneous emission (stochastic mode hopping). PS in VCSELs is the object of intensive experimental and theoretical work, as a thorough understanding of the dynamics of the switching is not only interesting from a physical point of view, but is also important for realising potential applications relying on fast polarisation modulation. We will present an extensive experimental characterisation of the dynamics of PS for different types of single transverse mode VCSELs. The current of PS can be varied in our devices through the elasto-optic effect by applying mechanical stress. Our modulation experiments around the PS current reveal a strong scaling of the maximum modulation frequency over more than eight orders of magnitude, as the PS current is varied from nearby threshold to about twice that value. We will furthermore present an accurate statistical analysis of the noise-driven mode hopping between the two polarisation states at fixed current. A similar scaling as for the maximum modulation frequency is observed for the residence times in one of the two polarization modes as the PS current is varied

© 2001 EPS