Patent Number: 6,167,070

Title: Optical semiconductor device and method of fabricating the same

Abstract: There is provided an optical semiconductor device including an optical waveguide structure having a quantum well layer and an optical confinement layer as a core layer, wherein the core layer has a thickness varying in a lengthwise direction of the optical waveguide to thereby have a function of spot-size conversion, and the quantum well layer is designed to have a band-gap energy which is constant within .+-.30 meV in the direction. The above-mentioned optical semiconductor device makes it possible to an optical gain to laser oscillation wavelength over all ranges of a resonator, and hence makes it no longer necessary to form a region only for spot-size conversion (SSC). This ensures that a device length can be as small as that of a conventional laser diode. In addition, lower threshold value characteristic and high temperature operation performance could be achieved, and a yield in devices per a wafer can be significantly enhanced.

Inventors: Sakata; Yasutaka (Tokyo, JP)

Assignee: NEC Corporation

International Classification: G02B 6/122 (20060101); H01S 5/34 (20060101); H01S 5/227 (20060101); H01S 5/10 (20060101); H01S 5/00 (20060101); G02B 6/12 (20060101); H01S 5/343 (20060101); H01S 5/50 (20060101); H01S 5/20 (20060101); H01S 003/085 ()

Expiration Date: 12/26/2017