Differential gain enhancement in a quantum dash laser using strong optical injection

摘要

Increased differential gain is typically realized through strain, quantum confinement, or p-type doping in the active region. These methods have been applied to quantum dots or dashes to raise the differential gain with limited success because the optical gain of these low dimensional systems saturates at modest values. Instead larger differential gain can be accessed at wavelengths blue-shifted from the gain peak and close to optical transparency using the threshold shift induced by optical injection. Using these approaches, greater than 50X improvement in the differential gain has been achieved in an injection-locked QDash FP laser compared to its free-running value.