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EP0121401A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Light modulation device

Assignee: Sumitomo Electric Industries Ltd
•
Filing: 1984-03-28
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Granted: —
•
Expires: 2004-03-28
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Abstract

Abstract A light modulation device comprises a substrate (1), a substrate layer (2), an optical waveguide layer (3) and buffer layers (4), in that order, formed of either all n-type or all p-type compound semiconductor crystal. In orderto capture the light in the optical waveguide layer, the composition ratio of the compound semiconductor is so determined that the refractive index is at least approximately 0.1% higher in the optical waveguide layers than in the substrate layer and in the buffer layers. Furthermore, the carrier density is low in the optical waveguide layer and in the buffer layers, so that the applied voltage is effectively applied mainly to the optical waveguide layer. Due to the construction of the light modulation device, strict control of the etching process is not required, the device has a low absorption loss of light, and it can be made as a monolithic optical integrated circuit.

Inventors

  • 👤 Kunio Tada
  • 👤 Yoshikazu C/O Osaka Works Nishiwaki
  • 👤 Shunji C/O Osaka Works Matsuoka

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-03 16:55
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/015; G02F1/025; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F1/3133; G02F1/0151; G02F2201/00; G02F2201/06; G02F2201/063; G02F2202/00; G02F2202/10; G02F2202/101

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 162 words
A light modulation device, comprising a substrate (1) of a compound semiconductor crystal having a high carrier density; a substrate layer (2) of a compound semiconductor crystal having a high carrier density and mounted on the substrate; an optical waveguide layer (3) of a compound semiconductor crystal having a low carrier density and mounted on the substrate layer; two buffer layers (4) of a compound semiconductor crystal having a low carrier density and mounted parallel to each other and closely spaced on the optical waveguide layer; an electrode (5) in ohmic contact with the substrate (1); and electrodes (6) in Schottky contact with the buffer layers, respectively; characteris,ed in that the substrate, the substrate layer, the optical waveguide layer, and the buffer layers are either all of n-type or all of p-type semiconductor; and in that the optical waveguide layer has a refractiv e index at least approximately 0.1% higher than any of those of the substrate layer and the buffer layers;.
Claim 2
Dependent Claim 162 words
A light modulation device, comprising a substrate (1) of a compound semiconductor crystal having a high carrier density; a substrate layer (2) of a compound semiconductor crystal having a high carrier density and mounted on the substrate; an optical waveguide layer (3) of a compound semiconductor crystal having a low carrier density and mounted on the substrate layer; two buffer layers (4) of a compound semiconductor crystal having a low carrier density and mounted parallel to each other and closely spaced on the optical waveguide layer; an electrode (5) in ohmic contact with the substrate (1); and electrodes (6) in Schottky contact with the buffer layers, respectively; characteris,ed in that the substrate, the substrate layer, the optical waveguide layer, and the buffer layers are either all of n-type or all of p-type semiconductor; and in that the optical waveguide layer has a refractiv e index at least approximately 0.1% higher than any of those of the substrate layer and the buffer layers;.
Claim 3
Dependent Claim 58 words
A device as claimed in claim 1, characterised in that the substrate (1) is of n + AluGa 1-u As; the substrate layer ( 2 ) is of n+ Al x Ga 1-x As; the optical waveguide layer (3) is of nAl z Ga 1-z As; and the buffer layers (4) are of nAl y Ga 1-y As.
Claim 4
Dependent Claim 59 words
A device as claimed in claim 1, characterised in that the substrate (1) is of p + Al u Ga 1-u As; the substrate layer (2) is of p + Al x Ga 1-x As; the optical waveguide layer (3) is of pAl z Ga 1-z As; and the buffer layers (4) are of pAl y Ga 1-y As.
Claim 5
Dependent Claim 50 words
A device as claimed in claim 2 or claim 3, characterised in that the carrier density is approximately 10 17 /cm 3 in the substrate (1) and in the substrate layer (2), and approximately 10 15 /cm 3 in the optical waveguide layer (3) and in the buffer layers (4).
Claim 6
Dependent Claim 35 words
A device as claimed in claim 1, characterised in that the substrate (1), the substrate layer (2), the optical waveguide layer (3), and the buffer layers (4) are formed of an InP compound semiconductor crystal.

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