Semiconductor laser device

• US 4,941,146 A
• Filed: 06/28/1989
• Issued: 07/10/1990
• Est. Priority Date: 06/29/1988
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kobayashi, Kenichi
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Epps, Georgia Y.
• Application Number:
  US07/372,593
• Time in Patent Office: 377 Days
• Field of Search: 372/45, 372/46, 372/44, 357/4, 357/17, 357/16
• US Class Current: 372/45.01
• CPC Class Codes: H01S 5/20 Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
• CPC Class Codes: H01S 5/2004 Confining in the direction perpendicular to the layer structure
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode

Abstract

A semiconductor laser device comprises an active layer of a refractive index n₁, 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 n₁, n₂ and n₃ meet a relation of "n₁ >n₃ >n₂ ", 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.

Claims

1. A semiconductor laser device, comprising:

a double heterostructure including an active layer and first and second inner cladding layers provided on both sides of said active layer, said double heterostructure being provided on a semiconductor substrate and a bandgap energy of said first and second inner cladding layers being greater than that of said active layer;

first and second outer cladding layers provided on both sides of said double heterostructure; and

first and second electrodes for applying a predetermined voltage across said double heterostructure;

wherein a refractive index of said active layer is greater than a refractive index of said first and second outer cladding layers, and said refractive index of said first and second outer cladding layers is greater than a refractive index of said first and second inner cladding layers

2. A semiconductor laser device, according to claim 1 wherein:

said first and second inner cladding layers are of a thickness dependent on a vertical radiation angle of an output light beam, and said first and second outer cladding layers are of a refractive index dependent on said vertical radiation angle.