Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.0×10?3. For the inner cladding layer, the diameter is 15-17 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 24-33 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.

Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.0×10?3. For the inner cladding layer, the diameter is 15-17 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 24-33 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.

Abstract: An optical fiber with a large effective area includes a core layer and a cladding layer. The core layer comprises an inner core layer having a radius of 1-4 ?m and a relative refractive index difference ?12 of ?0.2%??12<0% relative to the outer core layer, and an outer core layer having a radius of 4-7 ?m and a relative refractive index difference ?2 of ?0.15%-0.05%. ?12 remains unchanged or increases as the radius of the inner core layer increases. The cladding layer comprises an inner cladding layer cladding the core layer and having a radius of 7-20 ?m and a relative refractive index difference ?3 of ?0.5%˜?0.1%, a depressed cladding layer has a radius of 12-40 ?m, and a relative refractive index difference ?4 of ?1.0%˜?0.3%, and an outer cladding layer having a relative refractive index difference ?5 of ?0.2%˜?0.4%.

Abstract: A single-mode fiber with a large effective area comprises a core layer and a cladding layer. The core layer is cladded with an intermediate cladding layer, and a depressed cladding layer is provided outside the intermediate cladding layer. The core layer comprises a first fiber sub core layer having a radius r1 of 1.5-5 ?m and a relative refractive index difference ?n1 of 0.05-0.22%, and a second sub core layer having a unilateral radial width (r2?r1) of 1.5-5 ?m and a relative refractive index difference ?n2 of 0.15-0.34%, where ?n1 is less than ?n2. Accordingly, the optical fiber can reach an effective area equal to or greater than 120 ?m2 when the related parameters thereof are optimized.

Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.5×10?3. For the inner cladding layer, the diameter is 16.5-20 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 33-40 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.

Abstract: The invention relates to a rotary seal chuck of an optical fiber preform rod deposition lathe, comprising a fixed socket sleeve and a rotary shaft. The fixed socket sleeve is provided with a central hole base. The central hole base bears the rotary shaft through a bearing. An end of the central hole base is connected to an air hose. The rotary shaft is a hollow rotary shaft provided with a through hole. One end of the through hole communicates with the air hose, and the other end of the through hole is provided with a liner tube connecting sealing hole base. A magnetic fluid seal ring is disposed at a joint between an inner side of the rotary shaft and the central hole base of the fixed socket sleeve, to form a rotary dynamic seal. An outer side of the rotary shaft is connected to a rotary driving disk.

Abstract: A dispersion compensation fiber comprises a fiber core and cladding. The fiber core is a core layer mainly doped with germanium and having a positive relative refractive index difference. The cladding covering the fiber core comprises a trench cladding mainly doped with fluorine, an annular cladding mainly doped with germanium, a matching cladding mainly doped with fluorine, and an outermost mechanical cladding in order. Relative refractive index differences of the fiber core and the claddings are respectively: ?1% being 1.55% to 2.20%, ?2% being ?0.55% to ?0.30%, ?3% being 0.40% to 0.65%, ?4% being ?0.20% to ?0.01%, and ?5% being 0. Radius ranges, from R1 to R5, of the fiber core and the claddings are respectively: R1 being 1.4 to 1.7 ?m, R2 being 4.1 to 4.8 ?m, R3 being 6.7 to 8.8 ?m, R4 being 10 to 17 ?m, and R5 being 38 to 63 ?m.

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: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.5×10?3. For the inner cladding layer, the diameter is 16.5-20 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 33-40 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.