EP0032390A2
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EP
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Method of producing a preform rod for an optical fiber
Assignee: Hitachi Ltd
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Filing: 1981-01-09
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Granted: —
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Expires: 2001-01-09
Abstract
Abstract A glass layer (2); is formed inside a silica glass tube (3) and another glass layer (1) having a refractive index higher than that of the abovementioned glass layer (2) is formed on said glass layer (2). After these glass layers (1,2) are formed, one end of the glass tube (3) is collapsed. While the internal pressure of the glass tube is being reduced below the atmospheric pressure, the glass tube is caused to collapse by heating, thereby yielding a preform for an optical fiber. The optical fiber produced from this preform has the difference in the refractive indices of the two orthogonal major axes (x, y) of at least 1.6 x 10<sup>-4</sup> and maintains the linear polarization plane.
Inventors
- 👤 Hiroyoshi Matsumura
- 👤 Toshio Katsuyama
- 👤 Tsuneo Suganuma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 06:18
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/105; C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/01205; C03B37/01211; C03B37/01217; C03B37/014; C03B37/018; C03B37/01861; C03C; C03C13/00; C03C13/04; C03C13/045; C03B2201/00; C03B2201/06; C03B2201/08; C03B2201/10; C03B2203/00; C03B2203/10; C03B2203/12; C03B2203/22; C03B2203/30
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
50 words
An optical fiber including a core (1), a B 2 0 3 -containing cladding (2) and a jacketing (3), characterized in that the outer circumference of said core (1) and/or said cladding (2) is elliptical and the birefringence of said core (1) is at least 1.6 x 10 -4 .
Claim 2
Dependent Claim
50 words
An optical fiber including a core (1), a B 2 0 3 -containing cladding (2) and a jacketing (3), characterized in that the outer circumference of said core (1) and/or said cladding (2) is elliptical and the birefringence of said core (1) is at least 1.6 x 10 -4 .
Claim 3
Dependent Claim
29 words
The optical fiber of claim 1, characterized in that the ellipticity of the outer circumference of either said cladding (2) or said core (1) is at least 1 %.
Claim 4
Dependent Claim
23 words
The optical fiber of claim 2, characterized in that said cladding (2) contains at least 20 mol% of B 2 0 3 .
Claim 5
Dependent Claim
34 words
The optical fiber of any of claims 1 to 3, characterized in that said core (1) is circular and is formed of silica glass containing either Ge0 2 or P 2 0 5 .
Claim 6
Dependent Claim
34 words
The optical fiber of any of claims 1 to 4, characterized in that the concentration of B 2 0 3 contained in said cladding (2) increases monotonously towards the center of the optical fiber.
Claim 7
Dependent Claim
56 words
The optical fiber of any of claims 1 to 5, characterized in that the concentration of B 2 0 3 contained in said cladding (2) attains the maximum value of 20 mol% at an intermediate portion in the radial direction of said cladding (2) and thereafter decreases monotonously towards said jacket (3) and said core (1).
Claim 8
Dependent Claim
84 words
An optical fiber having an optical waveguide (20, 21) and a jacket (22, 23) mounted on said waveguide (20, 21), characterized in that said waveguide comprises a circular core (20) and a circular cladding (21) having a refractive index lower than that of said core (20), and said jacket consists of a first jacket (22) having an elliptical outer shape and formed on said waveguide (20, 21) and a second jacket (23) having a circular outer shape and formed on said first jacket (22).
Claim 9
Dependent Claim
84 words
An optical fiber having an optical waveguide (20, 21) and a jacket (22, 23) mounted on said waveguide (20, 21), characterized in that said waveguide comprises a circular core (20) and a circular cladding (21) having a refractive index lower than that of said core (20), and said jacket consists of a first jacket (22) having an elliptical outer shape and formed on said waveguide (20, 21) and a second jacket (23) having a circular outer shape and formed on said first jacket (22).
Claim 10
Dependent Claim
30 words
The optical fiber of claim 7, characterized in that the refractive index of said first jacket (22) is not lower by more than 0.2% than that of said cladding (21).
Claim 11
Dependent Claim
64 words
The optical fiber of claim 8, characterized in that said core (20) consists of silica glass containing at least one of GeO 2 and P 2 O 3 , said cladding (21) consists of silica glass and said first jacket (22) consists of silica glass containing at least one of GeO 2 and P 2 0 5 , and B 2 0 3 .
Claim 12
Independent Claim
98 words
A method of producing a preform rod for an optical fiber, characterized by the,steps of: forming a glass layer on the inner wall of a glass tube, said glass layer made of a glass material different from that of said glass tube; heating and collapsing a part of said glass tube having said glass layer formed thereon; reducing the internal pressure of said glass tube having a part thereof collapsed from an open portion at one end thereof; and moving the heating portion of said collapsed part while reducing the pressure thereby to form a solid glass rod.
Claim 13
Independent Claim
98 words
A method of producing a preform rod for an optical fiber, characterized by the,steps of: forming a glass layer on the inner wall of a glass tube, said glass layer made of a glass material different from that of said glass tube; heating and collapsing a part of said glass tube having said glass layer formed thereon; reducing the internal pressure of said glass tube having a part thereof collapsed from an open portion at one end thereof; and moving the heating portion of said collapsed part while reducing the pressure thereby to form a solid glass rod.
Claim 14
Dependent Claim
32 words
The method of claim 10, characterized in that the degree of vacuum in said step of reducing the internal pressure ranges from -1 mm to -20 mm in terms of water height.
Claim 15
Dependent Claim
97 words
The method of claim 10 or 11, characterized in that said step of forming said glass layer of a glass material different from that of said glass tube on the inner wall of said glass tube comprises forming sequentially a first glass layer containing B 2 0 3 and second and third glass layers on the inner wall of said glass tube in such a manner that when the thickness of said third and fourth layers are t 2 and t 1 , the inner diameter C' of said first glass layer satisfies the following relations: ,
Claim 16
Independent Claim
61 words
The method of any of claims 10 to 12, characterized in that said step of forming glass layer on the inner wall of said glass tube comprises forming a first glass layer having a softening point lower than that of said glass tube and then forming a second layer having a softening point higher than that of said first glass layer.
References Cited (Backward Citations)
No citation records indexed.
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