Abstract: Optical fiber combiner includes a plurality of input optical fibers having a core and a cladding surrounding the core, a bridge fiber having a portion that transmits a light beam entered from each of the input optical fibers, and a glass member fusion-spliced to an end face of the cladding and to a first end face of the bridge fiber. The end portions of the claddings of the plurality of input optical fibers are bundled on at least a first end face side, with the adjacent side surfaces of the claddings being in contact with each other. The glass member has an outer diameter greater than the diameter of the core and smaller than the outer diameter of the cladding. The adjacent glass members are in a non-fusion-spliced state.

Abstract: Optical fiber combiner includes a plurality of input optical fibers having a core and a cladding surrounding the core, a bridge fiber having a portion that transmits a light beam entered from each of the input optical fibers, and a glass member fusion-spliced to an end face of the cladding and to a first end face of the bridge fiber. The end portions of the claddings of the plurality of input optical fibers are bundled on at least a first end face side, with the adjacent side surfaces of the claddings being in contact with each other. The glass member has an outer diameter greater than the diameter of the core and smaller than the outer diameter of the cladding. The adjacent glass members are in a non-fusion-spliced state.

Abstract: An optical fiber combiner 1 has: a plurality of input optical fibers 20; a plurality of divergence angle reducing members 50 which lights emitted from the respective input optical fibers 20 enter and which emits the lights from the input optical fibers 20 at divergence angles made lower than divergence angles upon entrance; a bridge fiber 30 which the lights emitted from the respective divergence angle reducing members 50 enter and which has a tapered portion 34 which has a portion in which the lights propagate and a diameter of which is gradually reduced apart from a divergence angle reducing member 50 side; and an output optical fiber 40 which a light emitted from a side of the bridge fiber 30 opposite to the divergence angle reducing member 50 side enters.

Abstract: An optical fiber combiner 1 has: a plurality of input optical fibers 20; a plurality of divergence angle reducing members 50 which lights emitted from the respective input optical fibers 20 enter and which emits the lights from the input optical fibers 20 at divergence angles made lower than divergence angles upon entrance; a bridge fiber 30 which the lights emitted from the respective divergence angle reducing members 50 enter and which has a tapered portion 34 which has a portion in which the lights propagate and a diameter of which is gradually reduced apart from a divergence angle reducing member 50 side; and an output optical fiber 40 which a light emitted from a side of the bridge fiber 30 opposite to the divergence angle reducing member 50 side enters.

Abstract: An optical amplifier includes: a first optical fiber, through which seed light and excitation light propagate; an optical coupler that inputs the excitation light into the first optical fiber; a first lens to which the seed light and the excitation light output from the first optical fiber are input and which increases diameters of the seed light and the excitation light; a glass rod doped with rare earth elements to be excited by the excitation light, to which the seed light and the excitation light output from the first lens are input and which amplifies and outputs the seed light as output light; a second lens to which at least the output light output from the glass rod is input and which decreases a diameter of the output light; and a second optical fiber to which the output light output from the second lens is input.

Abstract: An optical amplifier includes: a first optical fiber, through which seed light and excitation light propagate; an optical coupler that inputs the excitation light into the first optical fiber; a first lens to which the seed light and the excitation light output from the first optical fiber are input and which increases diameters of the seed light and the excitation light; a glass rod doped with rare earth elements to be excited by the excitation light, to which the seed light and the excitation light output from the first lens are input and which amplifies and outputs the seed light as output light; a second lens to which at least the output light output from the glass rod is input and which decreases a diameter of the output light; and a second optical fiber to which the output light output from the second lens is input.

Abstract: An optical amplifier includes: a first optical fiber, through which seed light and excitation light propagate; an optical coupler that inputs the excitation light into the first optical fiber; a first lens to which the seed light and the excitation light output from the first optical fiber are input and which increases diameters of the seed light and the excitation light; a glass rod doped with rare earth elements to be excited by the excitation light, to which the seed light and the excitation light output from the first lens are input and which amplifies and outputs the seed light as output light; a second lens to which at least the output light output from the glass rod is input and which decreases a diameter of the output light; and a second optical fiber to which the output light output from the second lens is input.

Abstract: Optical fiber thermometer includes one optical fiber that relays light from the light source to a measuring unit, two parallel optical fibers that relay light from a mirror at the measuring unit to two light-receiving units, and an arithmetic processing circuit that calculates the temperature of the measuring unit from the ratio of electrical signals from the two light-receiving units; end surfaces of three optical fibers facing the reflecting face being fixed at an angle ? between the longitudinal direction of the optical fibers and the normal to the reflecting face that is not zero, the angle between the optical fibers for reception and projection being symmetrical based on the normal to the reflecting face. Each of the optical fibers is a single-mode fiber at the wavelength being used.

Abstract: [Object] An optical amplifier and a resonator capable of outputting output light having a high intensity are provided.

Abstract: An optical sensor includes a light source, a sensing unit, a first optical fiber transmitting light from the light source to the sensing unit, second and third optical fibers transmitting the light from a reflecting surface of the sensing unit to light-receiving portions, and a calculation unit calculating physical quantities from electrical signals from the light-receiving portions. End surfaces of these fibers opposed to the reflecting surface are fixed so that the longitudinal direction thereof and the normal line of the reflecting surface form an angle ?, the second and third optical fibers are parallel to each other, and the fixing angles of the first optical fiber and the second and third optical fibers are symmetric about the normal line. These optical fibers have a single mode in the wavelength of which the optical fibers are used. A depolarizer is interposed between the light source and the first optical fiber.

Abstract: An optical sensor includes a light source, a sensing unit, a first optical fiber transmitting light from the light source to the sensing unit, second and third optical fibers transmitting the light from a reflecting surface of the sensing unit to light-receiving portions, and a calculation unit calculating physical quantities from electrical signals from the light-receiving portions. End surfaces of these fibers opposed to the reflecting surface are fixed so that the longitudinal direction thereof and the normal line of the reflecting surface form an angle ?, the second and third optical fibers are parallel to each other, and the fixing angles of the first optical fiber and the second and third optical fibers are symmetric about the normal line. These optical fibers have a single mode in the wavelength of which the optical fibers are used. A depolarizer is interposed between the light source and the first optical fiber.

Abstract: This optical fiber thermometer includes one optical fiber for projection that relays light from the light source to a measuring unit, two optical fibers for light-reception that relay light reflected from a reflecting face of a mirror provided at the measuring unit to two light-receiving units, and an arithmetic processing circuit that calculates the pressure of the measuring unit from the ratio of electrical signals from the two light-receiving units; end surfaces of three optical fibers arranged to face the reflecting face being fixed such that an angle ? between the longitudinal direction of the optical fibers and the normal to the reflecting face is not zero, the two optical fibers for light-reception being parallel, fixing angles between each of them and the optical fiber for projection being symmetrical based on the normal to the reflecting face as a reference, and each of the optical fibers being a single-mode fiber at the wavelength being used, According to this invention, it is possible to provide an

Abstract: An optical sensor includes a light source, a sensing unit, a first optical fiber transmitting light from the light source to the sensing unit, second and third optical fibers transmitting the light from a reflecting surface of the sensing unit to light-receiving portions, and a calculation unit calculating physical quantities from electrical signals from the light-receiving portions. End surfaces of these fibers opposed to the reflecting surface are fixed so that the longitudinal direction thereof and the normal line of the reflecting surface form an angle ?, the second and third optical fibers are parallel to each other, and the fixing angles of the first optical fiber and the second and third optical fibers are symmetric about the normal line. These optical fibers have a single mode in the wavelength of which the optical fibers are used. A depolarizer is interposed between the light source and the first optical fiber.