Abstract: A low-dispersion single-mode fiber includes a core and claddings covering the core. The core layer has a radius in a range of 3-5 ?m and a relative refractive index difference in a range of 0.15% to 0.45%. The claddings comprise a first depressed cladding, a raised cladding, a second depressed cladding, and an outer cladding arranged sequentially from inside to outside. The first depressed cladding has a unilateral width in a range of 2-7 ?m and a relative refractive index difference in a range of ?0.4% to 0.03%. The raised cladding has a unilateral width in a range of 2-7 ?m and a relative refractive index difference in a range of 0.05% to 0.20%. The second depressed cladding has a unilateral width in a range of 0-8 ?m and a relative refractive index difference in a range of 0% to ?0.2%. The outer cladding is formed of pure silicon dioxide glass.

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 low-dispersion single-mode fiber includes a core and claddings covering the core. The core layer has a radius in a range of 3-5 ?m and a relative refractive index difference in a range of 0.15% to 0.45%. The claddings comprise a first depressed cladding, a raised cladding, a second depressed cladding, and an outer cladding arranged sequentially from inside to outside. The first depressed cladding has a unilateral width in a range of 2-7 ?m and a relative refractive index difference in a range of ?0.4% to 0.03%. The raised cladding has a unilateral width in a range of 2-7 ?m and a relative refractive index difference in a range of 0.05% to 0.20%. The second depressed cladding has a unilateral width in a range of 0-8 ?m and a relative refractive index difference in a range of 0% to ?0.2%. The outer cladding is formed of pure silicon dioxide glass.

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 rare earth-doped double-clad optical fiber includes a rare earth ion-doped fiber core, an inner cladding layer, and an outer cladding layer. A cross section of the inner cladding layer is a non-circular plane including at least two arcuate notches. According to the provided optical fiber, optical processing can be performed on a preform without changing a preform preparation process and a drawing process. The inner cladding is designed to have a non-circular planar structure having a cross section with at least two arcuate notches. While maintaining the same light absorption efficiency of pump light within the cladding layer, a preform polishing process is simplified, a risk of cracking the preform during polishing of multiple surfaces and a risk of contamination of the preform caused by impurities are reduced, wire drawing control precision is better, and comprehensive performance of the optical fiber is improved.

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 rare earth-doped double-clad optical fiber includes a rare earth ion-doped fiber core, an inner cladding layer, and an outer cladding layer. A cross section of the inner cladding layer is a non-circular plane including at least two arcuate notches. According to the provided optical fiber, optical processing can be performed on a preform without changing a preform preparation process and a drawing process. The inner cladding is designed to have a non-circular planar structure having a cross section with at least two arcuate notches. While maintaining the same light absorption efficiency of pump light within the cladding layer, a preform polishing process is simplified, a risk of cracking the preform during polishing of multiple surfaces and a risk of contamination of the preform caused by impurities are reduced, wire drawing control precision is better, and comprehensive performance of the optical fiber is improved.

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: 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 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 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 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 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 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%.