US5757986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated silicon pin diode electro-optic waveguide
Assignee: Mellanox Technologies Silicon Photonics Inc
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Filing: 1993-09-21
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Granted: 1998-05-26
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Expires: 2013-09-21
Abstract
Abstract The device comprises a layer of silicon separated from a substrate by a layer of insulating material. A rib having an upper surface and two side surfaces is formed in the layer of silicon to provide a waveguide for the transmission of optical signals. A lateral doped junction is formed between the side surfaces of the rib such that an electrical signal can be applied across the junction to control the density of charge carriers across a substantial part of the cross-sectional area of the rib thereby actively altering the effective refractive index of the waveguide.
Inventors
- 👤 Stephen James Crampton
- 👤 Arnold Peter Roscoe Harpin
- 👤 Andrew George Rickman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:50
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/015; G02F1/025; G02F1/0151; G02F1/0152; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F1/3133; G02F1/3137; G02F1/3138; G02F2201/00; G02F2201/06; G02F2201/063; G02F2202/00; G02F2202/10; G02F2202/105
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
152 words
An electro-optic device comprising: a layer of silicon separated from a substrate by a layer of insulating material with a rib comprising an upper surface and two side surfaces formed in the layer of silicon to provide a rib waveguide for the transmission of optical signals and means for controlling the density of free charge carriers in the rib waveguide so as to alter the effective refractive index of the rib waveguide, characterised in that said control means is in the form of a lateral doped junction comprising a p-doped region and an n-doped region on opposite sides of the rib to form a pin diode arranged such that an electrical signal can be applied laterally across the junction so as to inject free charge carriers into the rib waveguide and in that the dimensions of the rib waveguide forming the optical waveguide are large enough to be compatible with fibre optics.
Claim 2
Dependent Claim
152 words
An electro-optic device comprising: a layer of silicon separated from a substrate by a layer of insulating material with a rib comprising an upper surface and two side surfaces formed in the layer of silicon to provide a rib waveguide for the transmission of optical signals and means for controlling the density of free charge carriers in the rib waveguide so as to alter the effective refractive index of the rib waveguide, characterised in that said control means is in the form of a lateral doped junction comprising a p-doped region and an n-doped region on opposite sides of the rib to form a pin diode arranged such that an electrical signal can be applied laterally across the junction so as to inject free charge carriers into the rib waveguide and in that the dimensions of the rib waveguide forming the optical waveguide are large enough to be compatible with fibre optics.
Claim 3
Dependent Claim
25 words
A device as claimed in claim 1 in which the p-doped region and the n-doped region are symmetrically arranged on opposite sides of the rib.
Claim 4
Dependent Claim
37 words
A device as claimed in claim 1 in which the n-doped region and the p-doped region are separated by a central region comprising one of an intrinsic region, a pseudo intrinsic region and a lightly doped region.
Claim 5
Dependent Claim
22 words
A device as claimed in claim 3 in which the central region extends across substantially 25% of the width of the rib.
Claim 6
Dependent Claim
34 words
A device as claimed in claim 1 having electrical contacts which are electrically connected to the junction via doped regions in the layer of silicon which extends away from the sides of the rib.
Claim 7
Dependent Claim
35 words
A device as claimed in claim 1 in which the thickness of the layer of silicon from the top surface of the rib to the layer of insulation material is between 2 and 8 microns.
Claim 8
Dependent Claim
17 words
A device as claimed in claim 6 in which the layer of insulating material comprises silicon dioxide.
Claim 9
Dependent Claim
19 words
A device as claimed in claim 7 in which the layer of silicon dioxide is approximately 0.4 microns thick.
Claim 10
Dependent Claim
31 words
A device as claimed in claim 8 which has been formed from a conventional silicon-on-insulator wafer having a surface layer of silicon which has been epitaxially grown in increase its thickness.
Claim 11
Dependent Claim
60 words
A device as claimed in claim 1 in which the ratio (R:S) of the rib height (R) to the thickness (S) of the silicon layer and the ratio (R:W) of the rib height (R) to the rib width (W) are selected such that, for a given wavelength, only a fundamental mode in both the vertical and horizontal directions is propagated.
Claim 12
Dependent Claim
29 words
An optical phase modulator comprising a device as claimed in claim 1, the alteration of the refractive index being used to alter the effective length of the wave guide.
Claim 13
Dependent Claim
34 words
An optical switch comprising a device as claimed in claim 1, the alteration of the refractive index being used to alter the coupling between a first rib waveguide and a second rib waveguide thereof.
Claim 14
Dependent Claim
31 words
The use of a device as claimed in claim 1 as an optical phase modulator, the alteration of the refractive index being used to alter the effective length of the waveguide.
Claim 15
Dependent Claim
35 words
The use of a device as claimed in claim 1 as an optical switch, the alteration of the refractive index being used to alter the coupling between a first waveguide and a second waveguide thereof.
Claim 16
Dependent Claim
25 words
A device as claimed in claim 1 in which the p-doped region and then-doped region are provided in the side faces of the rib waveguide.
Claim 17
Dependent Claim
28 words
A device as claimed in claim 1 in which the p-doped region and the n-doped region are provided in the silicon layer on opposite sides of the rib.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-05-25 | 2001-11-24 | 2002-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-25 | 2005-11-24 | 2006-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-25 | 2009-11-24 | 2010-05-26 | $7700.00 | Window Closed / Lapsed |