EP0067017A1
Expired / Lapsed
EP
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Polarization plane maintaining optical fiber and fabricating method therefor
Assignee: Hitachi Ltd
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Filing: 1982-05-28
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Granted: —
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Expires: 2002-05-28
Abstract
Abstract Herein disclosed is an optical fiber having an intense ability to maintain the polarization plane, which is constructed of an optical waveguide having a circular core (1) and a circular cladding (2), a jacket (3) formed on the outer circumference of the optical waveguide which has an elliptical outer circumference, and a supporting portion (4) formed on the jacket. <??>In order to fabricate the above-specified optical fiber, a preformed rod is prepared by forming the jacket and the optical waveguide on the inner wall of a silica glass tube using materials which satisfy the relationship c2/a >/= 200/(100- gamma )-1, wherein: letter gamma stands for the ellipticity of the outer circumference of the jacket: letter c2 stands for the minor axis of the ellipse; and letter a stands for the radius of the circular optical waveguide. Then the silica glass tube is collapsed by heating while keeping its internal pressure lower than the atmospheric pressure by 1 to 20 mmH2O.
Inventors
- 👤 Hiroyoshi Matsumura
- 👤 Toshio Katsuyama
- 👤 Tsuneo Suganuma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 01:43
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/018; C03B37/01807; C03B37/01861; C03B37/01869; G; G02; G02B; G02B6/00; G02B6/10; G02B6/105; C03B2203/00; C03B2203/10; C03B2203/22; C03B2203/24; C03B2203/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
39 words
An optical fiber comprising: an optical waveguide (1,2) having a circular cross-section; a jacket (3) formed concentrically of said waveguide and having an elliptical outer circumference; and a supporting portion (4) formed on the outer circumference of said jacket.
Claim 2
Dependent Claim
39 words
An optical fiber comprising: an optical waveguide (1,2) having a circular cross-section; a jacket (3) formed concentrically of said waveguide and having an elliptical outer circumference; and a supporting portion (4) formed on the outer circumference of said jacket.
Claim 3
Dependent Claim
63 words
An optical fiber as set forth in Claim 1, wherein said optical waveguide includes: a circular core (1); and a circular cladding (2) formed concentrically of the outer circumference of said core and made of a material having a lower refractive index than that for said core, and wherein said jacket (3) has a refractive index substantially equal to that of said cladding.
Claim 4
Dependent Claim
34 words
An optical fiber as set forth in Claim 1 or Claim 2, wherein a core (1) of the waveguide is made of silica glass containing at least one of germanium dioxide and phosphorus pentoxide.
Claim 5
Dependent Claim
25 words
An optical fiber as set forth in any one of Claims 1 to 3, wherein the outer circumference of said supporting portion (4) is elliptical.
Claim 6
Dependent Claim
67 words
5, An optical fiber as set forth in Claim 1, wherein said optical waveguide includes: a circular core (1) 1 and a circular cladding (2) formed concentrically of the outer circumference of said core and made of a material having a lower refractive index than that for said core, and wherein said jacket (3) has an intermediate refractive index between those of said core and said cladding,
Claim 7
Dependent Claim
30 words
An optical fiber as set forth in Claim 2 or 5, wherein the radius of said core (1) is at most one half of the radius of said cladding (2).
Claim 8
Dependent Claim
44 words
An optical fiber as set forth in Claim 1, wherein the refractive index of said optical waveguide gradually reduces from the centre towards the outer side such that the minimum refractive index thereof is substantially equal to the refractive index of said jacket (3).
Claim 9
Dependent Claim
122 words
An optical fiber mother rod fabricating method comprising the steps of: forming a glass thin film (1,3) on the inner wall of a substrate comprising a silica glass tube (4); and subsequently collapsing said silica glass tube (4) while keeping its internal pressure lower than the external pressure, thereby fabricating a solid optical fiber mother rod, characterised in that said glass thin film forming step includes substeps of: first forming on the inner wall of said silica glass tube (4) a first glass thin film (3) having a lower softening point than that of said silica glass tube (4); and subsequently forming a second glass' thin film (1) having a higher softening point than that of said first glass thin film (3).
Claim 10
Dependent Claim
122 words
An optical fiber mother rod fabricating method comprising the steps of: forming a glass thin film (1,3) on the inner wall of a substrate comprising a silica glass tube (4); and subsequently collapsing said silica glass tube (4) while keeping its internal pressure lower than the external pressure, thereby fabricating a solid optical fiber mother rod, characterised in that said glass thin film forming step includes substeps of: first forming on the inner wall of said silica glass tube (4) a first glass thin film (3) having a lower softening point than that of said silica glass tube (4); and subsequently forming a second glass' thin film (1) having a higher softening point than that of said first glass thin film (3).
Claim 11
Dependent Claim
27 words
An optical fiber mother rod fabricating method as set forth in Claim 8, wherein said first glass thin film (3) is made of silica glass containing B203.
Claim 12
Dependent Claim
93 words
An optical fiber mother rod fabricating method as set forth in Claim 8 or 9, wherein said first and second glass thin films (3, 1) have their thicknesses within the range expressed by the following Equation: in which: letter γ stands for the ellipticity of the layer formed by said first glass thin film (3) in said optical fiber mother rod; letter c 2 stands for the length of the minor axis of the ellipse; and letter a stands for the radius of the core formed by said second glass thin film (1).
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US4106847A
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EP0032390A2
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