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Patent US5790737A successfully refreshed from Google Patents.
US5790737A
Expired / Lapsed
US
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Optical semiconductor device
Assignee: Mitsubishi Electric Corp
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Filing: 1996-08-12
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Granted: 1998-08-04
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Expires: 2016-08-12
Abstract
Abstract A semiconductor laser chip according to the present invention comprises: a p-type InP substrate; an InGaAsP active layer (optical waveguide) formed on said substrate; a p-n-p InP block layer formed on said substrate; a contact layer formed thereupon; an insulating film formed on said contact layer; a front surface electrode formed on said insulating film; a pair of alignment marks formed at the same time of the optical waveguide; and a back surface electrode formed on said substrate. The alignment marks are formed from the same material, i.e., the same crystal as said optical waveguide. Accordingly, it is possible to improve precision of the relative position between said optical waveguide and said alignment marks.
Inventors
- 👤 Toshitaka Aoyagi
- 👤 Yasunori Miyazaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:09
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4219; G02B6/422; G02B6/4221; G02B6/4224; H; H01; H01S; H01S5/00; H01S5/02; H01S5/022; H01S5/0235; H01S5/02375; H01S5/0238; H01S5/0201; H01S5/0202; H01S5/02355; H01S5/0237; H01S5/04; H01S5/042; H01S5/0425; H01S5/04256; H01S5/06; H01S5/065; H01S5/0651; H01S5/0653; H01S5/0655; H01S5/20; H01S5/2004; H01S5/2018; H01S5/2022; H01S5/22; H01S5/2205; H01S5/2222; H01S5/2223; H01S5/227; H01S5/2275
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
67 words
An optical semiconductor device comprising: a substrate; an optical waveguide disposed on said substrate and including, sequentially arranged, a first cladding layer, an active layer, and a second cladding layer; and an alignment mark disposed on said and having first, second, and third layers of essentially the same materials as and generally co-planar with said first cladding layer, said active layer, and said second cladding layer, respectively.
Claim 2
Dependent Claim
67 words
An optical semiconductor device comprising: a substrate; an optical waveguide disposed on said substrate and including, sequentially arranged, a first cladding layer, an active layer, and a second cladding layer; and an alignment mark disposed on said and having first, second, and third layers of essentially the same materials as and generally co-planar with said first cladding layer, said active layer, and said second cladding layer, respectively.
Claim 3
Dependent Claim
22 words
The optical semiconductor device according to claim 1, including a current blocking layer disposed on said substrate adjacent said second cladding layer.
Claim 4
Dependent Claim
29 words
The optical semiconductor device according to claim 2, including a groove electrically separating said active layer from said second layer, said current blocking layer being disposed in the groove.
Claim 5
Dependent Claim
32 words
The optical semiconductor device according to claim 2, including a first semiconductor layer, a second semiconductor layer, and a third semiconductor layer sequentially laminated in the groove as said current blocking layer.
Claim 6
Dependent Claim
17 words
The optical semiconductor device according to claim 2, wherein said current blocking layer includes an insulating film.
Claim 7
Dependent Claim
15 words
The optical semiconductor device according to claim 1, including a plurality of said alignment marks.
Claim 8
Dependent Claim
28 words
The optical semiconductor device according to claim 1, wherein said second layer of said alignment mark has a band gap energy narrower than materials surrounding said alignment mark.
Claim 9
Dependent Claim
33 words
The optical semiconductor device according to claim 1, including a fourth layer on said alignment mark and having a band gap energy no larger than the band gap energy of said active layer.
Claim 10
Dependent Claim
18 words
The optical semiconductor device according to claim 1, wherein said second layer is thicker than said active layer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-08-03 | 2002-02-02 | 2002-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-03 | 2006-02-02 | 2006-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-03 | 2010-02-02 | 2010-08-04 | $7700.00 | Window Closed / Lapsed |