Optical fiber, method for manufacturing optical fiber, and optical fiber preform
AssigneeFujikura Ltd.
InventorHisayuki Nakagome
Life of this patent
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Abstract
An optical fiber includes: a core; and a cladding layer disposed on an outer circumference of the core. A Cl concentration in the cladding layer is 0.029 wt % to 0.098 wt %. In the optical fiber, Δ2−Δ1≤0 dB/km is satisfied at a wavelength of 430 nm where Δ1 is a value of transmission loss before exposure of the optical fiber to hydrogen and Δ2 is a value of transmission loss after the exposure.
Claims6
An optical fiber comprising:
- a core;
- and
- a cladding layer disposed on an outer circumference of the core, wherein
- the core is formed of silicon dioxide that does not contain germanium,
- the cladding layer includes an inner cladding layer and an outer cladding layer disposed outside of the inner cladding layer,
- a refractive index of the outer cladding layer is higher than a refractive index of the inner cladding layer,
- an average Cl concentration distribution across a cross section of the cladding layer is 0.029 wt% to 0.098 wt%, and
- Δ2−Δ1<0 dB/km is satisfied at a wavelength of 430 nm, where Δ1 is a value of transmission loss before exposure of the optical fiber to hydrogen and Δ2 is a value of transmission loss after the exposure to pure hydrogen for at least 15 hours.
A method for manufacturing an optical fiber including a core and a cladding layer disposed on an outer circumference of the core, the method comprising:
- dehydrating the cladding layer with Cl-containing gas such that a Cl concentration in the cladding layer is 0.029 wt% to 0.098 wt%, wherein
- the core is formed of silicon dioxide that does not contain germanium,
- the cladding layer includes an inner cladding layer and an outer cladding layer disposed outside of the inner cladding layer,
- a refractive index of the outer cladding layer is higher than a refractive index of the inner cladding layer,
- the cladding layer is dehydrated with the Cl-containing gas such that an average Cl concentration distribution across a cross section of the cladding layer is 0.029 wt% to 0.098 wt%, and
- Δ2−Δ1<0 dB/km is satisfied at a wavelength of 430 nm, where Δ1 is a value of transmission loss before exposure of the optical fiber to hydrogen and Δ2 is a value of transmission loss after the exposure to pure hydrogen for at least 15 hours.
An optical fiber preform for manufacturing an optical fiber including a core and a cladding layer disposed on an outer circumference of the core, wherein
- the core is formed of silicon dioxide that does not contain germanium,
- the cladding layer includes an inner cladding layer and an outer cladding layer disposed outside of the inner cladding layer,
- a refractive index of the outer cladding layer is higher than a refractive index of the inner cladding layer,
- a soot that forms the cladding layer includes Cl,
- an average Cl concentration distribution across a cross section of the cladding layer formed by the soot is 0.029 wt% to 0.098 wt%, and
- Δ2−Δ1<0 dB/km is satisfied at a wavelength of 430 nm, where Δ1 is a value of transmission loss before exposure of the optical fiber to hydrogen and Δ2 is a value of transmission loss after the exposure to pure hydrogen for at least 15 hours.
Dependencies are inferred from the claim text.