Patent ID: 7460575
Filing Date: 2008-12-02
Classification: H01S

Abstract:
1. A semiconductor laser diode, comprising: a semiconductor substrate having an undulation for a feedback grating; an intermediate layer disposed on the semiconductor substrate and having the same undulation as the substrate; a lower separated confinement layer disposed on the intermediate layer, the lower separated confinement layer filling valleys of the undulation of the semiconductor substrate, a top surface of the lower separated confinement layer being substantially flat, the lower separated confinement layer having a refractive index different from a refractive index of the substrate; an active layer disposed on the lower separated confinement layer, the active layer generating the light diffracted by the undulation in the substrate; and an upper separated confinement layer disposed on the active layer, wherein the semiconductor substrate, the intermediate layer, and the lower separated confinement layer are n-type InP, AlInAsP, and AlGaInAs, respectively, wherein the intermediate layer relaxes a band discontinuity between the lower separated confinement layer and the semiconductor substrate; and wherein the substrate, the intermediate layer and the lower separated confinement layer forms the feedback grating.