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US3877052A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light-emitting semiconductor apparatus for optical fibers
Assignee: AT&T Inc
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Filing: 1973-12-26
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Granted: 1975-04-08
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Expires: 1993-12-26
Abstract
Abstract A semiconductor light-emitting diode (LED), which is substantially transparent to its own generated radiation, is coated with a reflecting layer having an exit aperture for transmission of optical radiation, for example, to an optical fiber. The reflecting layer includes a layer of dielectric in contact with the semiconductor, the dielectric layer itself being coated with an optically reflecting metal layer. The dielectric layer is made sufficiently thick to prevent the evanescent waves (of the totally internally reflected light in the semiconductor) from contacting the metal, thereby affording very close to 100 percent optical reflection of the optical rays in the semiconductor which are incident on the dielectric at greater than the critical angle. In addition, a significant portion of the semiconductor-dielectric interface is rough, thereby scattering (randomizing) the totally internally reflected rays in the semiconductor, which rays otherwise would have no chance of being accepted into the optical fiber. Thus, the overall coupling efficiency of optical radiation from the diode to the optical fiber is enhanced.
Inventors
- 👤 Richard Wayne Dixon
- 👤 William Baxter Joyce
- 👤 Daniel Leon Rode
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:11
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/84; H10H20/841; G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4204; H10H20/83; H10H20/831; H10H20/8314
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
234 words
A LIGHT-EMITTING APPARATUS WHICH COMPRISES A. AN ELECTROLUMINESCENT SEMICONDUCTOR BODY, INCLUDING AT LEAST ONE P-N JUNCTION AND A PAIR OF ELECTRODE CONTACTS TO SAID BODY FOR THE APPLICATION OF ELECTRICAL BIAS TO THE BODY FOR THE GENERATION OF OPTICAL RADIATION IN THE BODY, A SUBSTANTIAL PORTION OF SAID BODY BEING SUBSTANTIALLY TRANSPARENT TO SAID RADIATION AND AT LEAST A PORTION OF THE BPBOUNDARY SURFACE OF THE BODY BEING ROUGH, SAID PORTION OF THE SURFACE BEING SUFFICIENT IN AREA EXTENT TO SCATTER A SIGNIFICANT PORTION OF THE OPTICAL RADIATION IN THE BODY; B. A DIELECTRIC LAYER WHICH COATS THE SEMICONDUCTOR BODY EXCEPT FOR APERTURES FOR THE INSERTION OF ELECTRODE CONTACTS TO THE BODY AND EXCEPT FOR AT LEAST ONE OTHER APERTURE FOR THE ESCAPE OF OPTICAL RADIATION FROM THE BODY THROUGH AN EXIT PORT OF THE BODY, THE THICKNESS OF THE DIELECTRIC BEING SUFFICIENT TO ALOW FOR THE SPATIAL DECAY OVER SAID THICKNESS OF THE DIELECTRIC OF THOSE EVANESCENT WAVES OF LIGHT WHICH ARE TOTALLY INTERNALLY REFLECTED AT THE BOUNDARY OF THE SEMICONDUCTOR BODY WITH THE DIELECTRIC LAYER TO AN INSIGNIFICANT VALUE OF INTENSITY, THE REFRACTIVE INDEX OF THE DIELECTRIC BEING LESS THAN THAT OF THE SEMICONDUCTOR AT THE INTERFACE WITH SAID DIELECTRIC; AND C. A METAL LAYER COATING THE DIELECTRIC LAYER, THE METAL LAYER BEING SUITABLE FOR THE REFLECTION OF LIGHT TRANSMITTED THROUGH THE INTERFACE FORMED BY THE SEMICONDUCTOR BODY WITH THE DIELECTRIC LAYER.
Claim 2
Dependent Claim
234 words
A LIGHT-EMITTING APPARATUS WHICH COMPRISES A. AN ELECTROLUMINESCENT SEMICONDUCTOR BODY, INCLUDING AT LEAST ONE P-N JUNCTION AND A PAIR OF ELECTRODE CONTACTS TO SAID BODY FOR THE APPLICATION OF ELECTRICAL BIAS TO THE BODY FOR THE GENERATION OF OPTICAL RADIATION IN THE BODY, A SUBSTANTIAL PORTION OF SAID BODY BEING SUBSTANTIALLY TRANSPARENT TO SAID RADIATION AND AT LEAST A PORTION OF THE BPBOUNDARY SURFACE OF THE BODY BEING ROUGH, SAID PORTION OF THE SURFACE BEING SUFFICIENT IN AREA EXTENT TO SCATTER A SIGNIFICANT PORTION OF THE OPTICAL RADIATION IN THE BODY; B. A DIELECTRIC LAYER WHICH COATS THE SEMICONDUCTOR BODY EXCEPT FOR APERTURES FOR THE INSERTION OF ELECTRODE CONTACTS TO THE BODY AND EXCEPT FOR AT LEAST ONE OTHER APERTURE FOR THE ESCAPE OF OPTICAL RADIATION FROM THE BODY THROUGH AN EXIT PORT OF THE BODY, THE THICKNESS OF THE DIELECTRIC BEING SUFFICIENT TO ALOW FOR THE SPATIAL DECAY OVER SAID THICKNESS OF THE DIELECTRIC OF THOSE EVANESCENT WAVES OF LIGHT WHICH ARE TOTALLY INTERNALLY REFLECTED AT THE BOUNDARY OF THE SEMICONDUCTOR BODY WITH THE DIELECTRIC LAYER TO AN INSIGNIFICANT VALUE OF INTENSITY, THE REFRACTIVE INDEX OF THE DIELECTRIC BEING LESS THAN THAT OF THE SEMICONDUCTOR AT THE INTERFACE WITH SAID DIELECTRIC; AND C. A METAL LAYER COATING THE DIELECTRIC LAYER, THE METAL LAYER BEING SUITABLE FOR THE REFLECTION OF LIGHT TRANSMITTED THROUGH THE INTERFACE FORMED BY THE SEMICONDUCTOR BODY WITH THE DIELECTRIC LAYER.
Claim 3
Dependent Claim
94 words
Apparatus according to claim 1 in which the semiconductor body contains an intermediate layer of gallium aluminum arsenide sandwiched between an outer layer of P-type gallium aluminum arsenide and an outer layer of N-type gallium aluminum arsenide, the proportion of aluminum to gallium in the P-type and the N-type outer layers being sufficient to render the P-type and N-type layers substantially transparent to the optical radiation generated in the intermediate gallium arsenide layer, and the proportion of aluminum to gallium in the intermediate layer being significantly less than in both of the outer layers.
Claim 4
Dependent Claim
17 words
Apparatus according to claim 1 in which the dielectric layer is essentially a silicon oxide type material.
Claim 5
Dependent Claim
58 words
Apparatus according to claim 1 which further includes electrical circuit means for providing a voltage to energize the electroluminescent semiconductor to generate optical radiation and which further includes an optical fiber having an entrance port located in proximity to the exit port of the semiconductor body whereby optical radiation generated in the body is coupled into the fiber.
Claim 6
Dependent Claim
182 words
An electroluminescent apparatus which comprises a. a body substantially of transparent semiconductor material, including means for generating optical radiation in the body; b. a dielectric layer in physical contact with a substantial portion of the surface of the body, the thickness of the dielectric being sufficient to allow for the spatial decay over said thickness of the dielectric of those evanescent waves of light which are totally internally reflected in the body at the boundary of the body with the dielectric layer to an insignificant value of intensity; and c. a metal layer in physical contact with a substantial portion of the outer surface of the dielectric layer, the dielectric layer and the metal layer forming boundary walls for the optical radiation cavity formed by the body, in which at least a significant portion of the interface between the body and the dielectric is sufficiently rough for the randomization of the directions of propagation of optical rays generated in the body to enable said rays to be coupled through an exit port of the body in a significantly greater proportion than otherwise.
Claim 7
Dependent Claim
182 words
An electroluminescent apparatus which comprises a. a body substantially of transparent semiconductor material, including means for generating optical radiation in the body; b. a dielectric layer in physical contact with a substantial portion of the surface of the body, the thickness of the dielectric being sufficient to allow for the spatial decay over said thickness of the dielectric of those evanescent waves of light which are totally internally reflected in the body at the boundary of the body with the dielectric layer to an insignificant value of intensity; and c. a metal layer in physical contact with a substantial portion of the outer surface of the dielectric layer, the dielectric layer and the metal layer forming boundary walls for the optical radiation cavity formed by the body, in which at least a significant portion of the interface between the body and the dielectric is sufficiently rough for the randomization of the directions of propagation of optical rays generated in the body to enable said rays to be coupled through an exit port of the body in a significantly greater proportion than otherwise.
Claim 8
Dependent Claim
33 words
Apparatus according to claim 5 in which the refractive index of the dielectric is less than that of the body at the interface with the dielectric by a factor of at least two.
Claim 9
Dependent Claim
13 words
Apparatus according to claim 5 in which the dielectric is essentially silicon dioxide.
Claim 10
Dependent Claim
16 words
Apparatus according to claim 5 in which the dielectric is the native oxide of the body.
Claim 11
Dependent Claim
37 words
Apparatus according to claim 5 in which the metal layer has an aperture port for the coupling to an optical fiber of the optical radiation generated in the body in response to electricity applied to the body.
Claim 12
Dependent Claim
11 words
Apparatus according to claim 9 which further includes the optical fiber.
Claim 13
Dependent Claim
168 words
In combination, a. a body of semiconductor, including at least one P-N junction and a pair of electrode contacts to said body for the application of electrical bias to stimulate the generation of optical radiation in the body, whose external surface is surrounded by a first layer of dielectric material having a lower refractive index than that of the semiconductor, except for aperture portions of said surface for the insertion of electrodes and for the exit of optical radiation to at least one optical fiber; and b. a second layer coating the first layer suitable for the reflection of light transmitted through the first layer, at least a portion of the interface of the dielectric layer and the body being optically rough, the first layer being sufficiently thick for an exponential decay of intensity of evanescent waves emanating from the body towards the second layer to a value at the second layer which is on the average less than about 25 percent of its value in the body.
Claim 14
Dependent Claim
168 words
In combination, a. a body of semiconductor, including at least one P-N junction and a pair of electrode contacts to said body for the application of electrical bias to stimulate the generation of optical radiation in the body, whose external surface is surrounded by a first layer of dielectric material having a lower refractive index than that of the semiconductor, except for aperture portions of said surface for the insertion of electrodes and for the exit of optical radiation to at least one optical fiber; and b. a second layer coating the first layer suitable for the reflection of light transmitted through the first layer, at least a portion of the interface of the dielectric layer and the body being optically rough, the first layer being sufficiently thick for an exponential decay of intensity of evanescent waves emanating from the body towards the second layer to a value at the second layer which is on the average less than about 25 percent of its value in the body.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |