Linewidth enhancement factor of quantumdot lasers.

The linewidth enhancement factor (α) of inhomogenously broadened InAs/GaAs quantum dot (QD) lasers is studied taking into account the effect of the multi-discrete QD energy levels for both electrons and holes. The effect of size-fluctuation and the separation between the energy states on α for different applied bias is studied. Very small value of α (∼0.3) is obtained at high-applied bias. This value is smaller than the linewidth enhancement factor in quantum well lasers. An empirical formula for the linewidth enhancement factor is also derived. [ABSTRACT FROM AUTHOR]