Patent US4097258A successfully refreshed from Google Patents.
US4097258A
Expired / Lapsed
US
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Optical fiber
Assignee: Hoya Glass Works Ltd
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Filing: 1976-06-16
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Granted: 1978-06-27
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Expires: 1996-06-16
Abstract
Abstract An optical fiber comprising a core glass and a cladding glass therearound, wherein at least the core glass contains GeO 2 as an additive to increase the refractive index with respect to the cladding glass. The fiber glass is prepared by heat treating a starting glass to separate out a B 2 O 3 --Na 2 O-rich phase for subsequent acid leaching, and by sintering a residual glass with low concentrations of light absorbing impurities. Ingredients of the starting glass in weight percent are as follows: SiO 2 :25 - 80 B 2 o 3 :10 - 30 Na 2 O:3 - 12 GeO 2 :3 - 40 A1 2 o 3 : 0 - 4
Inventors
- 👤 Susumu Horikawa
- 👤 Kenji Nakagawa
- 👤 Yoshito Nogami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:34
CPC Classifications
C; C03; C03C; C03C13/00; C03C13/04; C03C13/045; C03C13/046; C03C25/00; C03C25/66; C03C25/68
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
152 words
In a method for preparing the core glass of an optical fiber comprising: heat treating a starting glass to cause phase separation, leaching with an acid to obtain a porous glass with low concentration of Mn, Fe, Co, Ni, Cu and Cr, and sintering the porous glass into a dense, transparent glass, wherein said starting glass is composed mainly of SiO 2 , Na 2 O, B 2 O 3 and GeO 2 and said heat-treating causes phase separation of an Na 2 O--B 2 O 3 rich phase and said leaching with an acid removes said Na 2 O--B 2 O 3 rich phase and a porous glass composed mainly of SiO 2 --GeO 2 is obtained; the improvement comprising said acid being a polyhydric and/or polycarboxylic organic acid such that undissolved Ge does not remain in the pores of the porous SiO 2 GeO 2 glass during said acid leaching.
Claim 2
Dependent Claim
152 words
In a method for preparing the core glass of an optical fiber comprising: heat treating a starting glass to cause phase separation, leaching with an acid to obtain a porous glass with low concentration of Mn, Fe, Co, Ni, Cu and Cr, and sintering the porous glass into a dense, transparent glass, wherein said starting glass is composed mainly of SiO 2 , Na 2 O, B 2 O 3 and GeO 2 and said heat-treating causes phase separation of an Na 2 O--B 2 O 3 rich phase and said leaching with an acid removes said Na 2 O--B 2 O 3 rich phase and a porous glass composed mainly of SiO 2 --GeO 2 is obtained; the improvement comprising said acid being a polyhydric and/or polycarboxylic organic acid such that undissolved Ge does not remain in the pores of the porous SiO 2 GeO 2 glass during said acid leaching.
Claim 3
Dependent Claim
83 words
The method of claim 1 wherein the starting glass consists essentially of, in weight percent, 25 to 80% SiO 2 , 10 to 30% B 2 O 3 , 3 to 12% Na 2 O, 3 to 40% GeO 2 and 0 to 4% Al 2 O 3 , and wherein the sum of SiO 2 and GeO 2 is not less than 55% and that the mole ratio of Na 2 O to B 2 O 3 is between 0.20 to 0.47.
Claim 4
Dependent Claim
27 words
The method of claim 1, wherein said organic acid is selected from the group consisting of oxalic acid, succinic acid, malonic acid, tartaric acid and glycolic acid.
Claim 5
Dependent Claim
11 words
The method of claim 3 wherein said acid is oxalic acid.
References Cited (Backward Citations)
US3843228A
Cited
US3758284A
Cited
US3884550A
Cited
US3938974A
Cited
US4046948A
Cited
US4063001A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |