United States Patent m
Kobayashi
Patent Number: Date of Patent:
[54] SEMICONDUCTOR LASER DEVICE
[75] Inventor: Kenichi Kobayashi, Tokyo, Japan
[73] Assignee: NEC Corporation, Tokyo, Japan
[21] Appl. No.: 372,593
[22] Filed: Jim. 28, 1989
[30] Foreign Application Priority Data
Jun. 29, 1988 [JP] Japan 63-164034
[51] Int. CI.* HOIS 3/19
[52] U.S. CI 372/45; 357/4;
357/16; 357/17; 372/46
[58] Field of Search 372/45, 46, 44; 357/4,
357/17, 16
[56] References Cited
FOREIGN PATENT DOCUMENTS
0015385 1/1986 Japan 372/45
0156788 7/1986 Japan 372/45
0220492 9/1986 Japan 372/45
OTHER PUBLICATIONS M. B. Panish et al., "Reduction of Threshold Current.
.. Carrier Confinement", Appl. Phys. Lett., vol. 22, No. 11, Jun. 1, 1973, pp. 590-591.
Primary Examiner—William L. Sikes
Assistant Examiner— Georgia Y. Epps
Attorney, Agent, or Firm—Sughrue, Mion, Zinn,
Macpeak & Seas
[57] ABSTRACT
A semiconductor laser device comprises an active layer of a refractive index ni, first and second inner cladding layers of a refractive index n2 and a bandgap energy greater than that of the active layer provided on the both sides of the active layer to form a double heterostructure, and fist and second outer cladding layers of a refractive index n3 provided on the both sides of the double heterostructure. The refractive indices ni, nz and n3 meet a relation of ... so that a vertical radiation angle of an output light beam is controlled in accordance with a thickness of the first and second inner cladding layers, and the refractive index n3, even if the active layer is thick.
2 Claims, 5 Drawing Sheets
90 ELECTRODE 80 CAP LAYER
70CURRET BLOCKING LAYER 50SECOND OUTER CLADDING LAYER
30SECOND INNER CLADDING LAYER •)0ACTIVE LAYER 20FIRST INNER CLADDING LAYER
40FIRST OUTER CLADDING LAYER
60SEMI CONDUCTOR SUBSTRATE 100 ELECTRODE
