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US4884859A
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Optical attenuator and manufacturing method for making same
Assignee: Seiko Instruments Inc
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Filing: 1988-08-15
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Granted: 1989-12-05
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Expires: 2008-08-15
Abstract
Abstract A simple method of manufacturing optical attenuators comprises heating a part of an optical fiber composed of a core and a cladding to a temperature around the softening point of the materials of the optical fiber and applying a tension and/or a twist to the optical fiber at a predetermined speed to form an optical attenuation area having fine cracks in the heated part of the optical fiber.
Inventors
- 👤 Hiroyoshi Yamamoto
- 👤 Toshiharu Takesue
- 👤 Naoki Kawawada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:09
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/264; G02B6/266
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
71 words
A method of manufacturing optical attenuators comprising the steps of: heating a part of an optical fiber composed of a core and a cladding to a temperature around the softening point thereof; and applying an external force at a predetermined speed to said optical fiber for generating fine cracks around the cladding to induce radiation loss therefrom, thereby forming an optical attenuation area in the heated part of said optical fiber.
Claim 2
Independent Claim
71 words
A method of manufacturing optical attenuators comprising the steps of: heating a part of an optical fiber composed of a core and a cladding to a temperature around the softening point thereof; and applying an external force at a predetermined speed to said optical fiber for generating fine cracks around the cladding to induce radiation loss therefrom, thereby forming an optical attenuation area in the heated part of said optical fiber.
Claim 3
Dependent Claim
31 words
The method of manufacturing optical attenuators according to claim 1, wherein said step of applying external force comprises applying tension to said fiber in the direction of the longitudinal axis thereof.
Claim 4
Dependent Claim
19 words
The method of manufacturing optical attenuators according to claim 1, wherein said heating is carried out with a burner.
Claim 5
Dependent Claim
44 words
An optical attenuator comprising: an optical fiber composed of a core and a cladding; and an optical attenuation portion of said optical fiber, said optical attenuation portion consisting of a plurality of radial cracks in the cladding to induce radiation loss from said core.
Claim 6
Dependent Claim
44 words
An optical attenuator comprising: an optical fiber composed of a core and a cladding; and an optical attenuation portion of said optical fiber, said optical attenuation portion consisting of a plurality of radial cracks in the cladding to induce radiation loss from said core.
Claim 7
Independent Claim
70 words
A method of manufacturing optical attenuators, comprising the steps of: heating a part of an optical fiber composed of a core and a cladding to a temperature around the softening point of the materials of said optical fiber; and applying a twisting force to said optical fiber around the longitudinal axis thereof at a predetermined speed to form an optical attenuation area in the heated part of said optical fiber.
Claim 8
Independent Claim
70 words
A method of manufacturing optical attenuators, comprising the steps of: heating a part of an optical fiber composed of a core and a cladding to a temperature around the softening point of the materials of said optical fiber; and applying a twisting force to said optical fiber around the longitudinal axis thereof at a predetermined speed to form an optical attenuation area in the heated part of said optical fiber.
Claim 9
Dependent Claim
67 words
Apparatus for producing optical attenuators, comprising: means for heating a portion of an optical fiber composed of a core and a cladding around the core to a predetermined temperature; and means for placing said optical fiber under predetermined tension sufficient to produce radial cracks in said cladding after said optical fiber has been heated to said predetermined temperature, thereby to induce radiation loss from said optical fiber.
Claim 10
Dependent Claim
67 words
Apparatus for producing optical attenuators, comprising: means for heating a portion of an optical fiber composed of a core and a cladding around the core to a predetermined temperature; and means for placing said optical fiber under predetermined tension sufficient to produce radial cracks in said cladding after said optical fiber has been heated to said predetermined temperature, thereby to induce radiation loss from said optical fiber.
Claim 11
Dependent Claim
19 words
The apparatus of claim 6, in which said predetermined temperature is approximately the softening point of said optical fiber.
Claim 12
Dependent Claim
27 words
The apparatus of claim 6, in which said means for placing said optical fiber under tension comprises means for inducing predetermined angular displacement in said optical fiber.
Claim 13
Dependent Claim
37 words
The apparatus of claim 8, comprising, in addition, means for monitoring the radiation loss induced in said optical fiber, and for terminating both said angular displacement and said heat when said radiation loss reaches a predetermined level.
Claim 14
Dependent Claim
19 words
The apparatus of claim 6, in which said means for applying heat to said optical fiber comprises a burner.
Claim 15
Dependent Claim
12 words
The attenuator of claim 4, in which said optical fiber comprises quartz.
Claim 16
Dependent Claim
20 words
The apparatus of claim 7, in which the optical fiber is quartz and said predetermined temperature is approximately 800° C.
Claim 17
Dependent Claim
26 words
The attenuator of claim 4, comprising, in addition, an encasement material surrounding said optical fiber and having a refractive index lower than that of said cladding.
Claim 18
Dependent Claim
13 words
The attenuator of claim 13, in which said encasement material comprises silicon gel.
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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) | 1992-12-04 | 1993-06-05 | 1993-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-04 | 1997-06-05 | 1997-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-04 | 2001-06-05 | 2001-12-05 | $7700.00 | Window Closed / Lapsed |