Abstract: A multicore fiber includes cores located at vertexes of a polygonal ring and a cladding including sub medium regions and covering the cores. A refractive index of the cladding is lower than a refractive index of the cores and higher than a refractive index of the sub medium regions. The sub medium regions are arranged at positions to reduce a crosstalk between adjacent cores of the cores.

Abstract: An optical fiber which, at an optical fiber connecting end having a plurality of voids around the periphery of a core, has a light-permeable substance, such as a resin or glass whose refractive index is lower than that of quartz type substances, filled in the voids adjacent to the connecting end. An optical fiber connecting section where an optical fiber having a plurality of voids in a clad around the periphery of a core is connected to another optical fiber, wherein the optical fiber is connected end-to-end to aforesaid another optical fiber through a refractive index matching agent whose refractive index at the minimum temperature in actual use is lower than that of the core.

Abstract: An optical fiber that has no bubbles in the ultraviolet ray curable resin filled inside the air holes to seal the end parts thereof, an end part processing method of the optical fiber, and an end part processing apparatus of the optical fiber, are provided. In an end part processing method of an optical fiber that is comprised of a core and a cladding formed around the core, the cladding having a refraction index lower than that of the core and has a plurality of air holes formed therein along the axis of the core, wherein the end part process of the optical fiber is to form sealed portions on the ends of the air holes by sealing them with ultraviolet ray curable resin, the method is characterized in that the sealed portion is formed by heating the end of the optical fiber.

Abstract: A multicore fiber includes cores located at vertexes of a polygonal ring and a cladding including sub medium regions and covering the cores. A refractive index of the cladding is lower than a refractive index of the cores and higher than a refractive index of the sub medium regions. The sub medium regions are arranged at positions to reduce a crosstalk between adjacent cores of the cores.

Abstract: An optical fiber that permits, even when the cladding outer diameter thereof is smaller than 125 ?m, an eased splicing with other optical fiber using a general-purpose ferrule, is provided. The optical fiber comprises: a first optical fiber having a first core and a first cladding having a cladding outer diameter smaller than 125 ?m, wherein the first cladding has a plurality of air holes that extend longitudinally along the axis of the first core; a second optical fiber having a second core to be spliced to the first core, and a second cladding having a cladding outer diameter larger than the outer diameter of the first cladding, wherein the second cladding is to be spliced to the first cladding; and a fusion splice formed between the end of the first optical fiber and the end of the second optical fiber by fusion.

Abstract: An optical fiber that has no bubbles in the ultraviolet ray curable resin filled inside the air holes to seal the end parts thereof, an end part processing method of the optical fiber, and an end part processing apparatus of the optical fiber, are provided. In an end part processing method of an optical fiber that is comprised of a core and a cladding formed around the core, the cladding having a refraction index lower than that of the core and has a plurality of air holes formed therein along the axis of the core, wherein the end part process of the optical fiber is to form sealed portions on the ends of the air holes by sealing them with ultraviolet ray curable resin, the method is characterized in that the sealed portion is formed by heating the end of the optical fiber.

Abstract: An optical fiber comprising: a core formed in a center axis area; an inner clad layer, disposed around the core, having a refractive index smaller than that of the core; a pore layer, disposed around the inner clad layer, having a plurality of elongated pores; and an outer clad layer, disposed around the pore layer, having a refractive index equal to or smaller than the refractive index of the core, wherein a length of the elongated pores is not larger than 200 m.

Abstract: An optical fiber laser, according to the present invention, has an optical fiber including a core to which a rare earth element is added and a clad disposed around the core, and also has an excitation light source for emitting excitation light incident on a side of the optical fiber. The optical fiber has a corrugated shape on the outer circumference of the clad along the longitudinal direction thereof; and the optical fiber is wound in a spiral form and is bundled in such a way that adjacent sides of the clad are brought into contact with one another.

Abstract: An optical connector according to the present invention comprises a ferrule and a V-groove board connected to the ferrule, wherein a first optical fiber and a second optical fiber being butt jointed in a V-groove formed in the V-groove board so as to be interconnected; the second optical fiber is connected to the first optical fiber through a refractive index matching material of cross-link curing type applied to an end surface on the V-groove board side of the first optical fiber; and spaces are provided in the V-groove so as to relax stress loaded on the refractive index matching material of cross-link curing type.

Abstract: The optical fiber 1 for an optical fiber laser is provided with a rare earth element doped core 2 doped with a rare earth element, and a cladding 3 formed at an outer periphery of the rare earth element doped core 2. In the optical fiber 1 for an optical fiber laser, the rare earth element doped core 2 is divided into a plurality of core regions 2a, 2b, . . . , 2n?1, 2n along a longitudinal direction of the optical fiber 1 and dopant concentrations of the rare earth element in respective core regions 2a, 2b, . . . , 2n?1, 2n are different from each other, in order to flatten a temperature distribution of the optical fiber 1 along the longitudinal direction.

Abstract: To provide a low-cost, high reliability and high-powered operation enabled optical fiber laser, in the optical fiber laser for oscillating a laser light by introducing an excitation light for exciting the rare earth elements into the optical fiber doped partially by the rare earth elements, the optical fiber is wrapped around the base member, and one part of the outer circumferential area of the wrapped optical fiber is processed in order to form a flat surface, and one face of the prism is made contacted to the flat surface, and the excitation light is introduced to another surface of the prism.

Abstract: A cladding is provided at an outer periphery of a solid-core doped with rare earth ions, and a metal layer is formed to be adjacent to the cladding to provide an optical fiber for a fiber laser device. The metal layer having an inner metal layer and an outer metal layer is disposed along an entire length of the optical fiber for a fiber laser device. An exciting light is incident to the optical fiber for a fiber laser device, and the exciting light is reflection-excited to emit a high power laser oscillation light. A monitoring current is constantly flown into the metal layer. When the disconnection of the optical fiber for a fiber laser device is detected based on the monitoring current, the energization of the optical fiber for a fiber laser device is stopped.

Abstract: The present invention can provide a stamper for minute structure transfer to be excellent in durability. The present invention is characterized by which a minute pattern as formed in one side of a substrate comes in contact with a material to be transferred and the minute pattern is transferred on a resin layer of a surface of the material to be transferred. At least one layer of a thin film is mounted on at least one side of both surfaces of the substrate, the substrate and the thin film are different in a coefficient of linear expansion each other, and the substrate is curved to swell up to be convex in the side of the minute pattern by an internal stress generated in the thin film.

Abstract: An optical fiber which, at an optical fiber connecting end having a plurality of voids around the periphery of a core, has a light-permeable substance, such as a resin or glass whose refractive index is lower than that of quartz type substances, filled in the voids adjacent to the connecting end. An optical fiber connecting section where an optical fiber having a plurality of voids in a clad around the periphery of a core is connected to another optical fiber, wherein the optical fiber is connected end-to-end to aforesaid another optical fiber through a refractive index matching agent whose refractive index at the minimum temperature in actual use is lower than that of the core.

Abstract: The present invention provides an optical fiber, for use in a fiber laser, from which a high-quality single-mode laser beam with high optical power is obtained and also provides a fiber laser that uses the optical fiber. The novel optical fiber, which includes a core to which a rare earth element is doped and a cladding formed around the core, amplifies excitation light to oscillate a laser beam. A mode filter is formed at a predetermined position in the longitudinal direction of the optical fiber.

Abstract: An optical fiber includes a core, a clad having a plurality of air holes at a periphery of the core, and a hardening resin filled in a sealed portion at an end of the plurality of air holes. The hardening resin after hardening has a fill length of 7 mm to 8 mm. An optical fiber connection structure includes the optical fiber with an end face butt-connected to another optical fiber. An optical connector includes the optical fiber, and a ferrule to which the optical fiber is attached.

Abstract: An optical fiber includes a core, a clad formed around the core, a plurality of holes being formed in the clad, and a UV curing optically-transparent resin which is filled in the holes and hardened. The UV curing optically-transparent resin has a Young's modulus of 8 to 500 MPa after hardening.

Abstract: An optical fiber laser, according to the present invention, has an optical fiber including a core to which a rare earth element is added and a clad disposed around the core, and also has an excitation light source for emitting excitation light incident on a side of the optical fiber. The optical fiber has a corrugated shape on the outer circumference of the clad along the longitudinal direction thereof; and the optical fiber is wound in a spiral form and is bundled in such a way that adjacent sides of the clad are brought into contact with one another.

Abstract: The optical fiber 1 for an optical fiber laser is provided with a rare earth element doped core 2 doped with a rare earth element, and a cladding 3 formed at an outer periphery of the rare earth element doped core 2. In the optical fiber 1 for an optical fiber laser, the rare earth element doped core 2 is divided into a plurality of core regions 2a, 2b, . . . , 2n?1, 2n along a longitudinal direction of the optical fiber 1 and dopant concentrations of the rare earth element in respective core regions 2a, 2b, . . . , 2n?1, 2n are different from each other, in order to flatten a temperature distribution of the optical fiber 1 along the longitudinal direction.

Abstract: The optical fiber 1 for an optical fiber laser is provided with a rare earth element doped core 2 doped with a rare earth element, a cladding 3 formed at an outer periphery of the rare earth element doped core 2, a core vicinity part 3? of the cladding 3 provided in vicinity of the rare earth element doped core 2 being doped with a refractive index increasing agent which reduces a relative refractive index difference between the core vicinity part 3? and the rare earth element doped core 2 to be 0.1% or less.