Patent ID: 11955775
Assignee: KABUSHIKI KAISHA TOSHIBA
Field: Optics (Instruments)
Classification: CPC H | IPC H

Claim 2:
3. A quantum cascade laser, comprising:
a first multilayer including a first layer and two second layers, the first layer including a ternary compound semiconductor represented by a compositional formula of In0.67Ga0.33As, the two second layers being of another ternary compound semiconductor represented by a compositional formula of In0.36Al0.64As, the first layer being provided between the two second layers; and
a second multilayer including a third layer and two fourth layers, the third layer including the ternary compound semiconductor, the two fourth layers being of another ternary compound semiconductor, the third layer being provided between the two fourth layers,
the first multilayer and the second multilayer being arranged in a first direction, the first to fourth layers being stacked in the first direction,
the two fourth layer each including a first sublayer and two second sublayers, the first sublayer being of a binary compound semiconductor of AlAs, the two second sublayers being of said another ternary compound semiconductor, the first sublayer being provided between the two second sublayers in the first direction,
wherein the first sublayer of the fourth layer has a layer thickness equal to or less than a layer thickness of double atomic-monolayers that include the binary compound semiconductor,
a conduction band edge energy of the first sublayer is higher than a conduction band edge energy of the second layers, and
wherein the first layer of the first multilayer further includes a sublayer of another binary compound semiconductor of GaAs.