Patent ID: 9099841
Filing Date: 2015-08-04
Classification: H01S

Abstract:
1. A semiconductor laser, comprising: a substrate; a first conduction-type cladding layer provided on the substrate; an active layer provided on the first conduction-type cladding layer; a second conduction-type cladding layer which is provided on the active layer and composed of a compound containing Al, the second conduction-type cladding layer including a stripe-shaped ridge structure serving as a current channel; a current block layer which is provided on a surface of the second conduction-type cladding layer except an upper surface of the ridge structure and is composed of a compound containing Al, the current block layer having a composition ratio of Al not higher than that of the second conduction-type cladding layer, a difference in the composition ratio of Al between the current block layer and the second conductive cladding layer being not more than 5%; a light absorption layer provided so as to be directly contacted on a surface of the current block layer that absorbs light at a laser oscillation wavelength, the light absorption layer composed of a material having a band gap larger than that of the p-type cladding layer in order to serve as a current block layer confining an injected current; and a contact layer formed on respective upper surfaces of the current block layer, a band discontinuity reduction layer, and the light absorption layer, wherein an entire space on both of side surface sides of the ridge structure of the second conduction-type cladding layer and immediately below the contact layer is filled with the light absorption layer, inserting the current blocking layer between the ridge structure and the light absorption layer, and wherein a saturable absorption region formed in the active layer and also under the current block layer absorbs and releases the laser light generated at the active layer for self-pulsation, the saturable absorption region being different from the light absorption layer.