Abstract: A method for manufacturing an optical fiber preform, including: a) providing a lining tube as a substrate tube, and doping and depositing by a PCVD or an MCVD process; b) in the reacting gas of silicon tetrachloride and oxygen, introducing a fluorine-containing gas for fluorine doping, introducing germanium tetrachloride for germanium doping, ionizing the reacting gas in the lining tube through microwaves to form plasma, depositing the plasma on the inner wall of the lining tube in the form of glass; c) after the completion of deposition, processing the deposited lining tube into a solid core rod by melting contraction through an electric heating furnace; d) sleeving the solid core rod into a pure quartz glass jacketing tube and manufacturing the two into an optical fiber preform; and e) allowing the effective diameter d of the optical fiber preform to become between 95 and 205 mm.

Abstract: A method for manufacturing an optical fiber preform, including: a) providing a lining tube as a substrate tube, and doping and depositing by a PCVD or an MCVD process; b) in the reacting gas of silicon tetrachloride and oxygen, introducing a fluorine-containing gas for fluorine doping, introducing germanium tetrachioride for germanium doping, ionizing the reacting gas in the lining tube through microwaves to form plasma, depositing the plasma on the inner wall of the lining tube in the form of glass; c) after the completion of deposition, processing the deposited lining tube into a solid core rod by melting contraction through an electric heating furnace; d) sleeving the solid core rod into a pure quartz glass jacketing tube and manufacturing the two into an optical fiber preform; and e) allowing the effective diameter d of the optical fiber preform to become between 95 and 205 mm.

Abstract: A single mode fiber having a core, an inner cladding, a depressed cladding, and an outer cladding composed of pure silica glass. The core is surrounded in sequence with the inner cladding and the depressed cladding. The core has silica glass doped with germanium and fluorine, with a diameter (a) of 8.0-8.8 ?m, a relative refractive index difference (?1) of 0.35-0.38%, and the contribution of fluoride (?F) is ?0.09±0.02%. The inner cladding has silica glass doped with germanium and fluorine, with a diameter (b) of 18-21 ?m and a relative refractive index difference (?2) of 0±0.02%. The depressed cladding has silica glass doped with fluorine, with a diameter (c) of 26-36 ?m and a relative refractive index difference (?32) at the external interface thereof is between ?0.22 and ?0.35%, and a relative refractive index difference (?31) at the internal interface thereof is between ?0.20 and ?0.35%, and ?32??31.

Abstract: A multimode fiber including a core and a cladding. The core has a radius (R1) of 24-26 ?m, the refractive index profile thereof is a parabola, and the maximum relative refractive index difference (?1) is 0.9-1.1%. The cladding surrounds the core and includes from inside to outside an inner cladding, a middle cladding, and an outer cladding; a radius (R2) of the inner cladding is 1.04-1.6 times that of the core, and a relative refractive index difference (?2) thereof is ?0.01-0.01%; the middle cladding is a graded refractive index cladding whose radius (R3) is 1.06-1.8 times that of the core, and a relative refractive index difference thereof is decreased from ?2 to ?4; and a radius (R4) of the outer cladding is 2.38-2.63 times that of the core, and a relative refractive index difference (?4) thereof is between ?0.20 and ?0.40%.

Abstract: A fiber preform, including: a fiber core rod and an outer cladding layer. The ratio of the diameter of the fiber core rod to the diameter of the core layer thereof is 2.1-2.8. The fiber core rod and a small fluorine-doped quartz glass tube are melted to form a core rod assembly. The ratio of the diameter difference between the core rod assembly and the fiber core rod to the diameter of the core layer is 0.5-2.2. The relative refractive index difference of fluorine-doped quartz glass relative to purified quartz glass ?F is ?0.20% to ?0.35%. The core rod assembly is arranged with a large purified quartz glass tube, or directly deposited with a SiO2 glass cladding layer. A ratio of an effective diameter of the fiber preform to the diameter of the core rod assembly is 2.0-5.6. Methods for manufacturing the preform and a fiber are also provided.

Abstract: A single mode fiber having a core, an inner cladding, a depressed cladding, and an outer cladding composed of pure silica glass. The core is surrounded in sequence with the inner cladding and the depressed cladding. The core has silica glass doped with germanium and fluorine, with a diameter (a) of 8.0-8.8 ?m, a relative refractive index difference (?1) of 0.35-0.38%, and the contribution of fluoride (?F) is ?0.09±0.02%. The inner cladding has silica glass doped with germanium and fluorine, with a diameter (b) of 18-21 ?m and a relative refractive index difference (?2) of 0±0.02%. The depressed cladding has silica glass doped with fluorine, with a diameter (c) of 26-36 ?m and a relative refractive index difference (?32) at the external interface thereof is between ?0.22 and ?0.35%, and a relative refractive index difference (?31) at the internal interface thereof is between ?0.20 and ?0.35%, and ?32??31.

Abstract: A multimode fiber including a core and a cladding. The core has a radius (R1) of 24-26 ?m, the refractive index profile thereof is a parabola, and the maximum relative refractive index difference (?1) is 0.9-1.1%. The cladding surrounds the core and includes from inside to outside an inner cladding, a middle cladding, and an outer cladding; a radius (R2) of the inner cladding is 1.04-1.6 times that of the core, and a relative refractive index difference (?2) thereof is ?0.01-0.01%; the middle cladding is a graded refractive index cladding whose radius (R3) is 1.06-1.8 times that of the core, and a relative refractive index difference thereof is decreased from ?2 to ?4; and a radius (R4) of the outer cladding is 2.38-2.63 times that of the core, and a relative refractive index difference (?4) thereof is between ?0.20 and ?0.40%.

Abstract: The invention relates to a low dispersion slope dispersion-shifted single-mode fiber for large capacity transmission comprising a core and a cladding. Said fiber is characterized in that said core has three to five core segments having different refractive index profiles, and said cladding has four to six cladding segments. The total dispersion slope of said fiber at 1550 nm is less than 0.060 ps/nm2·km, the zero dispersion wavelength is less than 1420 nm, the effective area ranges from 55 ?m2 to 65 ?m2, and the dispersion in the region of 1530 nm˜1565 nm ranges from 5.0 ps/nm2·km to 12.0 ps/nm2·km. The fiber has low dispersion slope, moderate dispersion, low attenuation, and excellent bend resistance performance. It is suitable for a high-speed (10 Gbits/s and 40 Gbits/s), large capacity, and long distance DWDM system.

Abstract: The present invention directs to a method of manufacturing low water peak single mode optical fiber, which comprises performing deposition in a substrate tube using PCVD technology, whereby a deposited layer of a certain construction design is formed on the inner wall of the substrate tube, melt contracting the substrate tube into a solid core rod according to melt contraction technology, producing an optical fiber preform by combining the core rod and a jacket tube of low hydroxyl content by means of RIT technology or by depositing an outer cladding on the outer surface of the core rod using OVD technology, sending the optical fiber preform into a fiber drawing furnace to draw it into an optical fiber, wherein: in the PCVD technology, the content of impurities in a gas mixture of raw materials, which is characterized by the infrared spectrum transmissivity thereof, is required to a transmissivity of 90% or greater, the water content in O2 is 100 ppb or less, the water content in C2F6 is 1000 ppb or less, the

Abstract: The invention relates to a low dispersion slope dispersion-shifted single-mode fiber for large capacity transmission comprising a core and a cladding. Said fiber is characterized in that said core has three to five core segments having different refractive index profiles, and said cladding has four to six cladding segments. The total dispersion slope of said fiber at 1550 nm is less than 0.060 ps/nm2·km, the zero dispersion wavelength is less than 1420 nm, the effective area ranges from 55 &mgr;m2 to 65 &mgr;m2, and the dispersion in the region of 1530 nm˜1565 nm ranges from 5.0 ps/nm2·km to 12.0 ps/nm2·km. The fiber has low dispersion slope, moderate dispersion, low attenuation, and excellent bend resistance performance. It is suitable for a high-speed (10 Gbits/s and 40 Gbits/s), large capacity, and long distance DWDM system.