US Patent 7756176 Interband tunneling intersubband transition semiconductor laser

An interband resonant tunneling intersubband transition laser is disclosed, and includes a semiconductor substrate, and a first cladding layer, an active region structure layer and a second cladding layer formed on the semiconductor substrate. The active region structure layer includes quantum well layers and quantum barrier layers that are alternately stacked and have a broken energy bandgap. Thus, the interband resonant tunneling intersubband transition laser operates in a cascade mode in which an intersubband radiative transition and interband tunneling of carriers consecutively and repetitively occur in the active region structure layer, and thus can achieve a high output from a simple, compact structure.