Broadened waveguide for interband cascade lasers

摘要

Interband cascade lasers having high-refractive index semiconductor spacer layers within the active regions are disclosed. Together with spacer layers which may be provided outside the active regions, broadened waveguides are formed which increase brightness and decrease divergence of the lasers. In one embodiment, current may be supplied laterally through the high-refractive index spacer layers. Carriers may be injected vertically through the active region from these contact layers, allowing selective functionality of some or all of the active region cascaded stages.