Abstract: A plurality of light emitting elements 11 are arranged in parallel with a constant pitch to provide a semiconductor laser bar 10. An optical waveguide 20 has a core part 21 for guiding a light emitted from each of the light emitting elements 11 and a cladding part 22 formed around the core part 21. An optical fiber 30 has a core 31 and a cladding 32 formed around the core 31 for confining the light to the core 31. The optical waveguide is bonded to a side surface of the optical fiber 30, and the light emitted from the semiconductor laser bar 10 is inputted to a side surface of the core 31 of the optical fiber 30 via the core part 21 of the optical waveguide 20.

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 includes a core, a clad formed around the core, a plurality of holes being formed in the clad, and a hardening resin having a moisture permeability equal to or less than 0.5 g/cm2·24 hr, in which the hardening resin is filled in a vicinity of an end face of the holes.

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 rare-earth element-added core for serving as a gain medium, and a cladding formed on a periphery of the core. Pump light propagated through the cladding is coupled into the core. The cladding is in an undulation shape in the longitudinal direction of the cladding. The undulation shape of the cladding is formed according to a grating period at which the pump light is totally reflected and propagated in the cladding. The core includes an undulation shape in a longitudinal direction of the core. The cladding includes an undulating inner cladding, and an outer cladding provided on a periphery of the inner cladding. The core and/or the cladding is circular or abnormally circular in its transverse cross section.

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: 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: 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: An optical connector having: a ferrule into which a first optical fiber is inserted; an optical fiber connector disposed at an back end of the ferrule; and a cross-linkable refractive index matching member attached onto an end face on a back end side of the first optical fiber. The end face on the back end side of the first optical fiber and an end face of a second optical fiber to be inserted into the optical fiber connector from a back end side thereof are to be connected by a butting connection. The cross-linkable refractive index matching member is formed such that a cross-linkable refractive index matching agent is coated on the end face on the back end side of the first optical fiber, and the coated agent is cross-linked and hardened.

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 connector having: a ferrule into which a first optical fiber is inserted; an optical fiber connector disposed at an back end of the ferrule; and a cross-linkable refractive index matching member attached onto an end face on a back end side of the first optical fiber. The end face on the back end side of the first optical fiber and an end face of a second optical fiber to be inserted into the optical fiber connector from a back end side thereof are to be connected by a butting connection. The cross-linkable refractive index matching member is formed such that a cross-linkable refractive index matching agent is coated on the end face on the back end side of the first optical fiber, and the coated agent is cross-linked and hardened.

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: 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.