Abstract: An optical fiber manufacturing method comprises preparing first base materials each of which includes at least one core forming part to form a core and a cladding forming part to form a cladding; performing a first elongating to form second base materials by forming a first bundle by bundling two or more base materials including at least one of the first base materials having been prepared at the preparing and by thermally elongating the first bundle; and performing a second elongating at least once to form a second bundle by bundling two or more base materials including at least one of the second base materials and by thermally elongating the second bundle, wherein the second bundle is thermally elongated up until the point when the optical fiber is formed at the second elongating.

Abstract: A holey fiber with significantly large effective core area is provided. The holey fiber comprises a core portion and a cladding portion at the circumference of the core portion. The cladding portion has plurality of holes distributed to shape triangular lattices around the core portion; wherein d/? is less than or equal to 0.42, the diameter of the holey fiber is larger than or equal to 580 ?m, an effective core area is larger than or equal to 15000 ?m2 at 1064 nm and a confinement loss is less than or equal to 0.1 dB/m at 1064 nm; where d is the hole diameter in ?m and ? is a lattice constant of the triangular lattice in ?m.

Abstract: A holey fiber has: a core region at a center of the holey fiber; a cladding region around the core region; a plurality of holes included in the cladding region, formed in layers around the core region, arranged to form a triangular lattice having a lattice constant ? of 2 micrometers to 5 micrometers, and each having a diameter of d micrometers; and a wavelength dispersion value of ?10 ps/nm/km to 10 ps/nm/km at a wavelength of 1050 nanometers when d/? is 0.3 to 0.47.

Abstract: A holey fiber with significantly large effective core area is provided. The holey fiber comprises a core portion and a cladding portion at the circumference of the core portion. The cladding portion has plurality of holes distributed to shape triangular lattices around the core portion; wherein d/? is less than or equal to 0.42, the diameter of the holey fiber is larger than or equal to 580 ?m, an effective core area is larger than or equal to 15000 ?m2 at 1064 nm and a confinement loss is less than or equal to 0.1 dB/m at 1064 nm; where d is the hole diameter in ?m and ? is a lattice constant of the triangular lattice in ?m.

Abstract: An optical transmission system employs an optical fiber as an optical transmission path that includes a holey fiber and a dispersion-compensating optical fiber. The holey fiber includes a core region that is formed at a center of the holey fiber and a cladding region having a plurality of holes around the core region at regular intervals. The dispersion-compensating optical fiber is connected close to the holey fiber and that collectively compensates wavelength dispersion of the holey fiber at an operation wavelength in at least two wavelength bands out of O band, E band, S band, C band, and L band within a predetermined range depending on a transmission rate.

Abstract: A photonic bandgap fiber includes a core formed by a hole at its center, an outer cladding formed around the core, and an inner cladding formed between the core and the outer cladding, in which a two-dimensional Bragg grating is formed by periodically arranging a medium having a different refractive index. An optical fiber is connected to the photonic bandgap fiber, which has wavelength dispersion equal to or larger than 0 ps/nm/km and smaller than wavelength dispersion of the photonic bandgap fiber and D/S value, which is obtained by dividing the wavelength dispersion by dispersion slope, larger than D/S value of the photonic bandgap fiber.

Abstract: A holey fiber has: a core region at a center of the holey fiber; a cladding region around the core region; a plurality of holes included in the cladding region, formed in layers around the core region, arranged to form a triangular lattice having a lattice constant ? of 2 micrometers to 5 micrometers, and each having a diameter of d micrometers; and a wavelength dispersion value of ?10 ps/nm/km to 10 ps/nm/km at a wavelength of 1050 nanometers when d/? is 0.3 to 0.47.

Abstract: A holey fiber includes a core portion and a cladding portion positioned around a periphery of the core portion. The cladding portion includes 12 to 36 holes that are arranged circularly at a radius of 36 to 48 micrometers around a center of the core portion and that each have a hole diameter of 2.0 to 11.0 micrometers. At a wavelength of 1064 nanometers the holey fiber substantially performs a single-mode operation and has an effective core area equal to or greater than 1500 ?m2.

Abstract: A holey fiber has at least: a core portion positioned at a center of the holey fiber; a cladding portion positioned around the core portion and including holes that are formed in layers around the core portion and that form a triangular lattice; d/? in a range of 0.43±0.03; ? of 20 to 24 micrometers; a single-mode operation demonstrated at a wavelength of 1550 nanometers; and an effective core area equal to or larger than 500 ?m2 at the wavelength of 1550 nanometers, wherein d is a diameter of each hole in micrometers, and ? is a lattice constant of the triangular lattice in micrometers.

Abstract: An optical transmission line includes a first optical fiber and a second optical fiber connected to the first optical fiber. The first optical fiber includes a core region formed at a center of the fiber and a cladding region formed around the core region. The cladding region includes air holes formed in a triangular lattice around the core region. The first optical fiber has a negative wavelength dispersion and a dispersion per slope of ?200 nm to ?50 nm at a wavelength of 1050 nm. The second optical fiber has a positive wavelength dispersion and the dispersion per slope of ?800 nm to ?50 nm at the wavelength of 1050 nm.

Abstract: A holey fiber has a core region, a cladding region surrounding the core region, air holes arranged around the core region, and a connection section extending from at least one end portion of the holey fiber. A refractive index of the core region in the connection section is higher than a refractive index of the cladding region without air holes in the connection section.

Abstract: An optical fiber includes a core region and a cladding region formed on an outer circumference of the core region. The cladding region includes a plurality of holes arranged around the core region and has a refractive index lower than a refractive index of the core region. A zero dispersion wavelength of the optical fiber is shorter than 1150 nanometers. The optical fiber propagates a light having a wavelength longer than 1000 nanometers exclusively in a fundamental mode of LP01 mode. An effective core area of the optical fiber is equal to or smaller than 12.0 ?m2 at a wavelength of 1064 nanometers.

Abstract: An optical fiber includes a core region and a cladding region formed on an outer circumference of the core region. The cladding region includes a plurality of holes arranged around the core region and has a refractive index lower than a refractive index of the core region. A zero dispersion wavelength of the optical fiber is shorter than 1150 nanometers. The optical fiber propagates a light having a wavelength longer than 1000 nanometers exclusively in a fundamental mode of LP01 mode. An effective core area of the optical fiber is equal to or smaller than 12.0 ?m2 at a wavelength of 1064 nanometers.

Abstract: Optical fibers and optical transmission systems, which are capable of broadband and large capacity single-mode optical transmission, and have low macrobends are provided. The optical fiber made from pure silica comprising a core region, a cladding region at the circumference of the core region a coating layer made from a resin at the circumference of the cladding region, and having a cutoff wavelength of shorter than 1530 nm, and positive dispersion at 1550 nm, bending loss of less than 10 dB/m at a bending diameter of 20 mm, and an effective core area of 120 ?m2.

Abstract: A holey fiber includes a core region formed at a center of the fiber and a cladding region formed on an outer circumference of the core region. The cladding region has a plurality of air holes arranged in a layered structure around the core region. The air holes are arranged in a triangular lattice such that a wavelength dispersion value at a wavelength of 1050 nm is in a range from ?10 ps/nm/km to 10 ps/nm/km when ? is in a range from 2 ?m to 5 ?m and d/? is in a range from 0.3 to 0.75, where d is hole diameter of each of the air holes in micrometers and ? is lattice constant of the triangular lattice in micrometers.

Abstract: An optical transmission line includes a first optical fiber and a second optical fiber connected to the first optical fiber. The first optical fiber includes a core region formed at a center of the fiber and a cladding region formed around the core region. The cladding region includes air holes formed in a triangular lattice around the core region. The first optical fiber has a negative wavelength dispersion and a dispersion per slope of ?200 nm to ?50 nm at a wavelength of 1050 nm. The second optical fiber has a positive wavelength dispersion and the dispersion per slope of ?800 nm to ?50 nm at the wavelength of 1050 nm.

Abstract: Optical fibers and optical transmission systems, which are capable of broadband and large capacity single-mode optical transmission, and have low macrobends are provided. The optical fiber made from pure silica comprising a core region, a cladding region at the circumference of the core region a coating layer made from a resin at the circumference of the cladding region, and having a cutoff wavelength of shorter than 1530 nm, and positive dispersion at 1550 nm, bending loss of less than 10 dB/m at a bending diameter of 20 mm, and an effective core area of 120 ?m2.

Abstract: A photonic bandgap fiber includes a core formed by a hole at its center, an outer cladding formed around the core, and an inner cladding formed between the core and the outer cladding, in which a two-dimensional Bragg grating is formed by periodically arranging a medium having a different refractive index. An optical fiber is connected to the photonic bandgap fiber, which has wavelength dispersion equal to or larger than 0 ps/nm/km and smaller than wavelength dispersion of the photonic bandgap fiber and D/S value, which is obtained by dividing the wavelength dispersion by dispersion slope, larger than D/S value of the photonic bandgap fiber.

Abstract: Optical fibers to form an optical transmission line suitable for WDM transmission in a wide-spreading wavelength band, having the following characteristics and parameters: a dispersion in absolute value of 0.5 ps/nm/km to 9 ps/nm/km in a wavelength band of 1430 nm to 1625 nm, a dispersion slope in absolute value of 0.04 ps/nm2/km or less at a wavelength of 1550 nm, a mode field diameter of 7 ?m or less at a wavelength of 1550 nm and a cable cutoff wavelength of less than 1430 nm; core 11 surrounded by cladding 7, core 11 being at least two-layered (first layer 1 at the center and second layer 2 surrounding the first layer; relative refractive index of glass layer ?1 with reference to the cladding being adjusted to not less than 0.6 but not more than 1.6%, relative refractive index of second layer ?2 with reference to the cladding being adjusted to a negative value.

Abstract: A holey fiber includes a core region and a cladding region surrounding the core region and having air holes arranged around the core region. The cladding region includes an inner cladding layer surrounding the core region and an outer cladding layer surrounding the inner cladding layer. Furthermore, viscosities of the core region and the inner cladding layer are set lower than a viscosity of the outer cladding layer.