Abstract: A polarization-maintaining multi-core fiber includes a plurality of fiber core areas and a main outer cladding. The fiber core areas include one central fiber core area, and two or more than two outer fiber core areas equidistantly and uniformly arranged around the central fiber core area that is a polarization-maintaining fiber core area. Each outer fiber core area includes a fiber core and an inner cladding surrounding a core layer. A portion outside the fiber core areas is the main outer cladding. The fiber can greatly enhance spectral efficiency of an optical transmission system, and improve fiber communication capacity. The arrangement of the polarization-maintaining fiber core area provides a waveguide structure with a function of maintaining polarized light, which can be used for transmission of local light.

Abstract: An array-type polarization-maintaining multi-core fiber includes a main outer cladding, fiber core units, and stress units. The fiber core units and the stress units are arranged to form a unit array including one central unit and any unit in the unit array being equidistantly arranged from adjacent units thereof. Provided is at least one pair of stress units, each pair of stress units being arranged symmetrical about one fiber core unit to form a polarization-maintaining fiber core unit. The fiber core units each include a fiber core and an inner cladding surrounding a core layer. A portion outside the fiber core units and the stress units is the main outer cladding. The fiber can greatly enhance spectral efficiency of an optical transmission system, and improve fiber communication capacity.

Abstract: An array-type polarization-maintaining multi-core fiber includes a main outer cladding, fiber core units, and stress units. The fiber core units and the stress units are arranged to form a unit array including one central unit and any unit in the unit array being equidistantly arranged from adjacent units thereof. Provided is at least one pair of stress units, each pair of stress units being arranged symmetrical about one fiber core unit to form a polarization-maintaining fiber core unit. The fiber core units each include a fiber core and an inner cladding surrounding a core layer. A portion outside the fiber core units and the stress units is the main outer cladding. The fiber can greatly enhance spectral efficiency of an optical transmission system, and improve fiber communication capacity.

Abstract: A polarization-maintaining multi-core fiber includes a plurality of fiber core areas and a main outer cladding. The fiber core areas include one central fiber core area, and two or more than two outer fiber core areas equidistantly and uniformly arranged around the central fiber core area that is a polarization-maintaining fiber core area. Each outer fiber core area includes a fiber core and an inner cladding surrounding a core layer. A portion outside the fiber core areas is the main outer cladding. The fiber can greatly enhance spectral efficiency of an optical transmission system, and improve fiber communication capacity. The arrangement of the polarization-maintaining fiber core area provides a waveguide structure with a function of maintaining polarized light, which can be used for transmission of local light.

Abstract: An anti-cracking panda-type polarization-maintaining optical fiber includes a cladding layer, stress layers, and a fiber core. The fiber core is located in the center of the cladding layer. The stress layers are located symmetrically at two sides of the fiber core with a distance away from the fiber core and are located within the cladding layer. Each stress layer is enclosed at edges of their outer sides by a transition layer with a gradient refractive index. By providing the transition layer with the gradient refractive index at the edge of the outer side of the stress layer, the pressure stress at the edge of the stress layer is decomposed and released, so as to avoid cracks at the edge of the polished stress layer on the end of the optical fiber, and thus optimizes the performance of the polarization-maintaining optical fiber by decreasing the room temperature polishing cracking rate.

Abstract: A multimode optical fiber includes a core and a cladding covering the core. The core has a radius in a range of 23.75-26.25 ?m. A refractive index profile of the core has a graded refractive index distribution with a refractive index distribution index ? in a range of 1.80-1.89. The core has a maximum relative refractive index difference ?1% in a range from 1.0% to 1.15%. The multimode optical fiber has a fusion loss less than or equal to 0.08 dB. The multimode optical fiber is applied in a middle-and-long distance distributed temperature-measuring system, and a temperature-measuring distance of the system reaches 10 km to 27 km. The system includes a pulsed laser light source, a wavelength division multiplexer, an avalanche photodiode, a data acquisition device, an upper computer, and the temperature-measuring multimode optical fiber.

Abstract: An anti-cracking panda-type polarization-maintaining optical fiber includes a cladding layer, stress layers, and a fiber core. The fiber core is located in the center of the cladding layer. The stress layers are located symmetrically at two sides of the fiber core with a distance away from the fiber core and are located within the cladding layer. Each stress layer is enclosed at edges of their outer sides by a transition layer with a gradient refractive index. By providing the transition layer with the gradient refractive index at the edge of the outer side of the stress layer, the pressure stress at the edge of the stress layer is decomposed and released, so as to avoid cracks at the edge of the polished stress layer on the end of the optical fiber, and thus optimizes the performance of the polarization-maintaining optical fiber by decreasing the room temperature polishing cracking rate.

Abstract: A multimode optical fiber includes a core and a cladding covering the core. The core has a radius in a range of 23.75-26.25 ?m. A refractive index profile of the core has a graded refractive index distribution with a refractive index distribution index ? in a range of 1.80-1.89. The core has a maximum relative refractive index difference ?1% in a range from 1.0% to 1.15%. The multimode optical fiber has a fusion loss less than or equal to 0.08 dB. The multimode optical fiber is applied in a middle-and-long distance distributed temperature-measuring system, and a temperature-measuring distance of the system reaches 10 km to 27 km. The system includes a pulsed laser light source, a wavelength division multiplexer, an avalanche photodiode, a data acquisition device, an upper computer, and the temperature-measuring multimode optical fiber.

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: 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 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 low attenuation single mode optical fiber includes a core layer and claddings. The core layer has the relative refractive index difference (RRID) ?1 ranging from ?0.1% to +0.1% and the radius R1 ranging from 4.0 ?m to 6.0 ?m. The claddings have three claddings layers surrounding the core layer. The RRID of the first cladding layer ?2 ranges from ?0.2% to ?0.6%, and the radius R2 thereof ranges from 10 ?m to 22 ?m. The RRID of the second cladding layer ?3 is less than ?2. The RRID and radius of the first cladding layer and the RRID and radius of the second cladding layer satisfy the relationship of: V=(?2??3)×(R3?R2), and the value of V ranges from 0.15% ?m to 0.8% ?m. The third cladding layer is all the layers that closely surround the second cladding layer, and the RRID of each layer is greater than ?3.

Abstract: A low attenuation single mode optical fiber includes a core layer and claddings. The core layer has the relative refractive index difference (RRID) ?1 ranging from ?0.1% to +0.1% and the radius R1 ranging from 4.0 ?m to 6.0 ?m. The claddings have three claddings layers surrounding the core layer. The RRID of the first cladding layer ?2 ranges from ?0.2% to ?0.6%, and the radius R2 thereof ranges from 10 ?m to 22 ?m. The RRID of the second cladding layer ?3 is less than ?2. The RRID and radius of the first cladding layer and the RRID and radius of the second cladding layer satisfy the relationship of: V=(?2??3)×(R3?R2), and the value of V ranges from 0.15% ?m to 0.8% ?m. The third cladding layer is all the layers that closely surround the second cladding layer, and the RRID of each layer is greater than ?3.

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: The invention relates to a method for manufacturing low PMD single-mode fiber and a fiber manufactured by said method. The twisting system is mounted at the downstream side of a normal fiber-drawing tower. The manner of twisting does not change the fiber-drawing path, the axis of twisting wheels periodically swing in a plane which is parallel to the fiber-drawing direction. The fiber moving at high speed makes the outer surfaces of the twisting wheels to rotate round the axis of the fiber, when an angle between the plane in which the twisting wheels are located and the fiber-drawing direction exists, the component of the angular velocity in the radial direction of the fiber reacts on the fiber and makes the fiber to twist, and the twist propagates to the soften region of the glass material at the fiber-drawing upstream in the form of mechanical wave, a plastic deformation is produced and set up in the newly drawn fiber.