US4372641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical waveguide termination
Assignee: AT&T Inc
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Filing: 1980-06-27
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Granted: 1983-02-08
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Expires: 2000-06-27
Abstract
Abstract Optical communications networks may be implemented by means of a patterned layer of an optically transparent material on a substrate. Where an optical path terminates, e.g., at an on-off switch, it is desirable to optically terminate a waveguide so as to minimize spurious signals due to reflection. The invention provides for optical termination of a waveguide by essentially complete absorption of light. Absorption is effected in a portion of the waveguide which comprises light absorbing centers such as, e.g., carbon or metal particles, anions, cations, or molecules which absorb light at desired wavelengths. Absorbing centers may be comprised in a central portion of a waveguide or, more conveniently, in a portion adjacent to a central portion. In the interest of minimizing reflections, interaction between light and absorbing centers increases gradually in a direction of light propagation as may be due to gradually increasing concentration of absorbing centers or to taper in a waveguide cladding portion, core portion, or absorbing portion.
Inventors
- 👤 Leo F. Johnson
- 👤 LeGrand G. Van Uitert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:33
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/1228
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
142 words
Optical communications device comprising a substrate-supported waveguide which is elongated in a direction of light propagation and which comprises a central portion in which index of refraction decreases by less than 1 percent in directions away from a center line of said central portion, said device being characterized in that a portion of said waveguide, here designated as an absorbing portion, comprises absorbing centers which absorb optical radiation at one or several wavelengths, said absorbing centers being present in said portion so as to result in gradually increasing interaction between said absorbing centers and light propagating in said direction and said absorbing centers being present in said portion in an amount sufficient for attenuation of said radiation by at least 30 decibel over a distance which is less than or equal to 10 centimeter and greater than or equal to 0.1 millimeter.
Claim 2
Dependent Claim
142 words
Optical communications device comprising a substrate-supported waveguide which is elongated in a direction of light propagation and which comprises a central portion in which index of refraction decreases by less than 1 percent in directions away from a center line of said central portion, said device being characterized in that a portion of said waveguide, here designated as an absorbing portion, comprises absorbing centers which absorb optical radiation at one or several wavelengths, said absorbing centers being present in said portion so as to result in gradually increasing interaction between said absorbing centers and light propagating in said direction and said absorbing centers being present in said portion in an amount sufficient for attenuation of said radiation by at least 30 decibel over a distance which is less than or equal to 10 centimeter and greater than or equal to 0.1 millimeter.
Claim 3
Dependent Claim
24 words
Device of claim 1 in which said distance is less than or equal to 1 centimeter and greater than or equal to 1 millimeter.
Claim 4
Dependent Claim
27 words
Device of claim 1 in which said absorbing portion is comprised in said central portion and in which concentration of absorbing centers increases gradually in said direction.
Claim 5
Dependent Claim
31 words
Device of claim 1 in which said absorbing portion is comprised in a cladding portion on said core portion and in which concentration of absorbing centers increases gradually in said direction.
Claim 6
Dependent Claim
20 words
Device of claim 1 in which said absorbing portion is on a cladding portion whose thickness diminishes in said direction.
Claim 7
Dependent Claim
26 words
Device of claim 1 in which said absorbing portion is on said core portion and in which thickness of said absorbing portion increases in said direction.
Claim 8
Dependent Claim
26 words
Device of claim 1 in which said absorbing portion is on a cladding portion which is on a central portion whose thickness diminishes in said direction.
Claim 9
Dependent Claim
38 words
Device of claim 7 in which tapering is such that said direction of light propagation meets the interface between said central portion and said cladding portion at an angle which is less than or equal to 10 degrees.
Claim 10
Dependent Claim
12 words
Device of claim 1 in which said absorbing centers are metal particles.
Claim 11
Dependent Claim
12 words
Device of claim 1 in which said absorbing centers are carbon particles.
Claim 12
Dependent Claim
15 words
Device of claim 1 in which said absorbing centers are substitutional atoms, ions, or molecules.
Claim 13
Dependent Claim
15 words
Device of claim 1 in which said absorbing centers are interstitial atoms, ions, or molecules.
Claim 14
Dependent Claim
11 words
Device of claim 1 in which said absorbing centers are vacancies.
References Cited (Backward Citations)
US3185945A
Cited
US3948583A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-07 | 1986-08-09 | 1987-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-07 | 1990-08-09 | 1991-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-07 | 1994-08-09 | 1995-02-08 | $7700.00 | Window Closed / Lapsed |