Patent ID: 6690699
Filing Date: 2004-02-10
Classification: B82Y,H01S

Abstract:
An apparatus for a laser, comprising:an optical waveguide having an optical core layer and optical cladding layers on opposite sides of the optical core layer, the optical core layer comprising an optical gain medium having first and second active layers and an injector layer interposed between the first and second active layers, the active layers having upper minibands and lower minibands, the active and injector layers comprising semiconductor superlattice structures; and a Fabry-Perot cavity, the optical gain medium being located in the Fabry-Perot cavity; and wherein the injector layer has a miniband that transports charge carriers from the lower miniband of the first active layer to an excited state in the upper miniband of the second active layer in response to application of a voltage across the optical gain medium, a lower edge of the miniband of the injector layer having a higher energy than a lower edge of the upper miniband of the second active layer when the voltage is applied; wherein the apparatus is a quantum cascade laser and the mismatch between the lower edges of the miniband of the injector layer and the upper miniband of the second active layer in response to the applied voltage is larger than an energy associated with the line width of laser light from the quantum cascade laser.