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US4406518A
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Single-mode-transmission optical fiber and a method of manufacturing the same
Assignee: Hitachi Ltd
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Filing: 1981-02-20
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Granted: 1983-09-27
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Expires: 2001-02-20
Abstract
Abstract A single-mode-transmission optical fiber comprises a core of a radius a having an arbitrary (non constant) refractive index distribution n(r) in the radial direction r, the index distribution being expressed by n2(r)=n12{1-2 DELTA of(r)}, and a cladding having a constant refractive index n2, the radius a of the core being: <IMAGE> In these expressions, n1 denotes a maximum refractive index of the core, lambda denotes a transmission light wavelength, <IMAGE> and a normalized frequency V is expressed by <IMAGE> Y is a solution Y in the case where X and Y are solutions of simultaneous equations: <IMAGE> of a function which is expressed by: <IMAGE> <IMAGE> <IMAGE> +TR <IMAGE>
Inventors
- 👤 Hiroyoshi Matsumura
- 👤 Toshio Katsuyama
- 👤 Tsuneo Suganuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:18
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/036; G02B6/03616; G02B6/03622; G02B6/03633; C; C03; C03B; C03B37/00; C03B37/01; C03B37/02; C03B37/025; C03B37/0253; G02B6/028; G02B6/0281; C03B2203/00; C03B2203/10; C03B2203/22; C03B2203/24; G02B6/03605; G02B6/03611
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
129 words
A single-mode optical fiber comprising: a light conducting core, the cross section of which has a prescribed radius a; and a cladding layer surrounding said core, said cladding layer having a constant index of refraction n 2 throughout; and wherein the index of refraction of said core has a non-constant distribution function, and the electric field distribution E(r) of the dominant mode propagating through said single-mode optical fiber and the propagation constant β of said single-mode optical fiber are made equal to the electric field distribution E s (r) of the dominant mode propagating through a stepped index optical fiber and the propagation constant β s of the stepped index optical fiber, respectively, where r is the radius of the single-mode optical fiber and the stepped index optical fiber.
Claim 2
Dependent Claim
129 words
A single-mode optical fiber comprising: a light conducting core, the cross section of which has a prescribed radius a; and a cladding layer surrounding said core, said cladding layer having a constant index of refraction n 2 throughout; and wherein the index of refraction of said core has a non-constant distribution function, and the electric field distribution E(r) of the dominant mode propagating through said single-mode optical fiber and the propagation constant β of said single-mode optical fiber are made equal to the electric field distribution E s (r) of the dominant mode propagating through a stepped index optical fiber and the propagation constant β s of the stepped index optical fiber, respectively, where r is the radius of the single-mode optical fiber and the stepped index optical fiber.
Claim 3
Dependent Claim
134 words
A single-mode optical fiber comprising: a cladding which has a constant refractive index n 2 , and a core of a radius a which is surrounded by said cladding and the refractive index distribution of which is greater than said refractive index n 2 and has in the radial direction r an arbitrary index distribution n(r) expressed by n 2 (r)=n 1 2 {1-2Δ o f(r)} (where 0≦f(r)≦1), the radius a of said core being: ##EQU32## X and Y being solutions of simultaneous equations of: ##EQU33## of a function which is expressed as follows, by letting n 1 denote a maximum refractive index of said core and λ denote a transmission light wavelength thereof, so that the relative index difference thereof is denoted by ##EQU34## and that a normalized frequency is denoted by ##EQU35##
Claim 4
Dependent Claim
134 words
A single-mode optical fiber comprising: a cladding which has a constant refractive index n 2 , and a core of a radius a which is surrounded by said cladding and the refractive index distribution of which is greater than said refractive index n 2 and has in the radial direction r an arbitrary index distribution n(r) expressed by n 2 (r)=n 1 2 {1-2Δ o f(r)} (where 0≦f(r)≦1), the radius a of said core being: ##EQU32## X and Y being solutions of simultaneous equations of: ##EQU33## of a function which is expressed as follows, by letting n 1 denote a maximum refractive index of said core and λ denote a transmission light wavelength thereof, so that the relative index difference thereof is denoted by ##EQU34## and that a normalized frequency is denoted by ##EQU35##
Claim 5
Independent Claim
112 words
A method of manufacturing a single-mode optical fiber wherein a preform is formed and is drawn at a high temperature into the optical fiber comprising the step of measuring the refractive index distribution of the preform after completion thereof, solutions X and Y of simultaneous equations of: ##EQU36## being obtained as to a function which is expressed as follows, by letting f(r) denote the refractive index distribution and d a radius of a core of the preform: ##EQU37## the optical-fiber drawing ratio in the drawing at the high temperature being made greater than: ##EQU38## (where n 2 denotes a maximum refractive index of the preform core, and Δ a relative index difference).
Claim 6
Independent Claim
112 words
A method of manufacturing a single-mode optical fiber wherein a preform is formed and is drawn at a high temperature into the optical fiber comprising the step of measuring the refractive index distribution of the preform after completion thereof, solutions X and Y of simultaneous equations of: ##EQU36## being obtained as to a function which is expressed as follows, by letting f(r) denote the refractive index distribution and d a radius of a core of the preform: ##EQU37## the optical-fiber drawing ratio in the drawing at the high temperature being made greater than: ##EQU38## (where n 2 denotes a maximum refractive index of the preform core, and Δ a relative index difference).
Claim 7
Dependent Claim
51 words
A method of manufacturing a single-mode fiber as defined in claim 3, wherein the step of forming the preform comprises: forming a material to become a core part, on an inner wall of a silica tube by the CVD process, and heating the resultant silica tube into a solid glass rod.
Claim 8
Dependent Claim
55 words
A method of manufacturing a single-mode fiber as defined in claim 3, wherein the step of forming the preform comprises: forming materials to become a cladding part and a core part, on an inner wall of a silica tube successively by a CVD process, and heating the resultant silica tube into a solid glass rod.
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) | 1986-09-26 | 1987-03-28 | 1987-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-26 | 1991-03-28 | 1991-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-26 | 1995-03-28 | 1995-09-27 | $7700.00 | Window Closed / Lapsed |