Abstract: An optical fiber end processing method includes the steps of: an optical fiber fixing step of fixing two parts of the optical fiber; a first heating step of heating a tip end side part of the optical fiber between two fixed parts fixed in the optical fiber fixing step, and melting the optical fiber of the tip end side heating part; a second heating step of heating a part on a base end side of the optical fiber between the fixed parts away from the tip end side heating part in a state that two parts of the optical fiber are fixed, and making the holes of the optical fiber disappear; and a removing step of removing the tip end side heating part after the second heating step.

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 end processing method includes fixing two portions of an optical fiber, heating and fusing the optical fiber between the two fixed portions, to form a first heat fusion region, heating and fusing the optical fiber fixed between the two fixed portions unit while fixing the two fixed portions, moving a heat fusion unit from a side of the first heat fusion region toward a base end side of the optical fiber, and pushing a heat fusion portion of the optical fiber in a direction of shortening a length of the heat fusion portion, to form a second heat fusion region continuous to the first heat fusion region and in which the air holes of the optical fiber disappear; and removing the first heat fusion region by cutting the optical fiber within the second heat fusion region after the second heat fusion forming.

Abstract: There is provide an optical fiber end processing method, for processing an end portion of an optical fiber having a core and a clad surrounding the core, comprising: fixing two places of the optical fiber; firstly heating a part at a tip end side of the optical fiber between fixed parts fixed at two places, thereby melting the optical fiber at the heated part at the tip end side; secondly heating a part at a base end side of the optical fiber between the fixed parts away from the heated part at the tip end side in a state that the optical fiber is fixed at two places, thereby forming an expanded core region which is formed by expanding a diameter of the core by diffusing the dopant included in the optical fiber; and removing at least the heated part at the tip end side.

Abstract: There is provide an optical fiber end processing method, for processing an end portion of an optical fiber having a core and a clad surrounding the core, comprising: fixing two places of the optical fiber; firstly heating a part at a tip end side of the optical fiber between fixed parts fixed at two places, thereby melting the optical fiber at the heated part at the tip end side; secondly heating a part at a base end side of the optical fiber between the fixed parts away from the heated part at the tip end side in a state that the optical fiber is fixed at two places, thereby forming an expanded core region which is formed by expanding a diameter of the core by diffusing the dopant included in the optical fiber; and removing at least the heated part at the tip end side.

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 end processing method includes fixing two portions of an optical fiber, heating and fusing the optical fiber between the two fixed portions, to form a first heat fusion region, heating and fusing the optical fiber fixed between the two fixed portions unit while fixing the two fixed portions, moving a heat fusion unit from a side of the first heat fusion region toward a base end side of the optical fiber, and pushing a heat fusion portion of the optical fiber in a direction of shortening a length of the heat fusion portion, to form a second heat fusion region continuous to the first heat fusion region and in which the air holes of the optical fiber disappear; and removing the first heat fusion region by cutting the optical fiber within the second heat fusion region after the second heat fusion forming.

Abstract: There is provide an optical fiber end processing method, for processing an end portion of an optical fiber having a core and a clad surrounding the core, comprising: fixing two places of the optical fiber; firstly heating a part at a tip end side of the optical fiber between fixed parts fixed at two places, thereby melting the optical fiber at the heated part at the tip end side; secondly heating a part at a base end side of the optical fiber between the fixed parts away from the heated part at the tip end side in a state that the optical fiber is fixed at two places, thereby forming an expanded core region which is formed by expanding a diameter of the core by diffusing the dopant included in the optical fiber; and removing at least the heated part at the tip end side.

Abstract: An optical fiber end processing method includes the steps of: an optical fiber fixing step of fixing two parts of the optical fiber; a first heating step of heating a tip end side part of the optical fiber between two fixed parts fixed in the optical fiber fixing step, and melting the optical fiber of the tip end side heating part; a second heating step of heating a part on a base end side of the optical fiber between the fixed parts away from the tip end side heating part in a state that two parts of the optical fiber are fixed, and making the holes of the optical fiber disappear; and a removing step of removing the tip end side heating part after the second heating step.

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 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 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 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 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 coiled cord having a coil construction in which an optical fiber cord is spirally bent to obtain lengthwise stretchability, wherein the fiber coiled cord is provided with a stretch length control member which restricts lengthwise elongation.

Abstract: An optical fiber cord which is a single core optical fiber cord having an outer diameter of 1.2 mm or less, and has a structure in which an optical fiber core wire having a resin coating is provided at the center, a tensile-strength-fiber layer is provided around the outer periphery of the optical fiber core wire, and a coating layer is further provided around the outer periphery of the tensile-strength-fiber layer, wherein the coating layer is composed of a non-halogen fire-retardant resin, is disclosed. This optical fiber cord has excellent fire retardant, mechanical and handling properties, although the outer diameter thereof is made smaller.

Abstract: An optical fiber coiled cord having a coil construction in which an optical fiber cord is spirally bent to obtain lengthwise stretchability, wherein the fiber coiled cord is provided with a stretch length control member which restricts lengthwise elongation.

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: A single core optical fiber cord having an outer diameter of 1.2 mm or less, and having a structure in which an optical fiber core wire having a resin coating provided at the center, a tensile-strength-fiber layer around the periphery of the optical fiber core wire, and a coating layer around the outer periphery of the tensile-strength-fiber layer is provided. The coating layer can be composed of a non-halogen fire-retardant resin. The optical fiber cord has excellent fire retardant, mechanical and handling properties, although the outer diameter thereof is 1.2 mm or less.