Abstract: A high-bandwidth bend-insensitive multimode fiber includes a core laver and a cladding including an inner cladding, a depressed cladding, and an outer cladding arranged sequentially from inside to outside. The core layer is a silicon dioxide glass layer co-doped with germanium, phosphorus (P), and fluorine (F) and has a refractive index profile in a shape of a parabola, a distribution index in a range of 2.0-2.3, a radius in a range of 23-27 ?m, and a maximum relative refractive index difference in a range of 0.9-1.2% at its center. A contribution amount of P at the center is in a range of 0.01-0.30%. A doping amount of F increases from the center to the edge of the core layer. A contribution amount of F at the center and edge of the core layer is in range of 0.0% to ?0.1%, and ?0.40% to ?0.20%, respectively.

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: 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: A high-bandwidth bend-insensitive multimode fiber includes a core laver and a cladding including an inner cladding, a depressed cladding, and an outer cladding arranged sequentially from inside to outside. The core layer is a silicon dioxide glass layer co-doped with germanium, phosphorus (P), and fluorine (F) and has a refractive index profile in a shape of a parabola, a distribution index in a range of 2.0-2.3, a radius in a range of 23-27 ?m, and a maximum relative refractive index difference in a range of 0.9-1.2% at its center. A contribution amount of P at the center is in a range of 0.01-0.30%. A doping amount of F increases from the center to the edge of the core layer. A contribution amount of F at the center and edge of the core layer is in range of 0.0% to ?0.1%, and ?0.40% to ?0.20%, respectively.

Abstract: A small core-diameter graded-index optical fiber include a core layer and a cladding having an inner cladding layer, a depressed cladding layer, and an outer cladding layer from inside to outside thereof. The core layer has a parabolic refractive index profile with a distribution index in a range of 1.9-2.1, a radius in a range of 10-21 ?m, and a ?1 max in a range of 0.7-1.7% at a core layer center, and is a silica glass layer co-doped with germanium, phosphorus, and fluoride. The inner cladding layer is a pure silica layer or an F-doped silica glass layer, and has a unilateral width in a range of 0.5-5 ?m and a ?2 in a range of ?0.4-0%. The depressed cladding layer has a unilateral width in a range of 2-10 ?m and a ?3 in a range from ?0.8% to ?0.2%. The outer cladding layer is a pure silica glass layer.

Abstract: A small core-diameter graded-index optical fiber include a core layer and a cladding having an inner cladding layer, a depressed cladding layer, and an outer cladding layer from inside to outside thereof. The core layer has a parabolic refractive index profile with a distribution index in a range of 1.9-2.1, a radius in a range of 10-21 ?m, and a ?1 max in a range of 0.7-1.7% at a core layer center, and is a silica glass layer co-doped with germanium, phosphorus, and fluoride. The inner cladding layer is a pure silica layer or an F-doped silica glass layer, and has a unilateral width in a range of 0.5-5 ?m and a ?2 in a range of ?0.4-0%. The depressed cladding layer has a unilateral width in a range of 2-10 ?m and a ?3 in a range from ?0.8% to ?0.2%. The outer cladding layer is a pure silica glass layer.