Abstract: An optical fiber bundle structure includes: plural optical fiber core wires; a crossing preventing member; and a grasping member. Further, the crossing preventing member has slits and the widths of the slits positioned at the respective sides are each equal to or larger than a difference between: a length of one side of a polygon circumscribing the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of one side of a polygon circumscribing the plural optical fiber core wires at the leading end.

Abstract: An optical fiber bundle structure includes: plural optical fiber core wires; a crossing preventing member; and a grasping member. Further, the crossing preventing member has slits and the widths of the slits positioned at the respective sides are each equal to or larger than a difference between: a length of one side of a polygon circumscribing the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of one side of a polygon circumscribing the plural optical fiber core wires at the leading end.

Abstract: An optical fiber bundle structure includes: plural optical fiber core wires; a crossing preventing member; and a grasping member. Further, the crossing preventing member has slits and the widths of the slits positioned at the respective sides are each equal to or larger than a difference between: a length of one side of a polygon circumscribing the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of one side of a polygon circumscribing the plural optical fiber core wires at the leading end.

Abstract: A laser device includes: a seed light source configured to output a laser light having a single mode; a multicore fiber including at least one core group having at least one core, each of the core in the core group being optically coupled to neighboring cores; and an optical coupler configured to input the laser light to the core group, wherein in the multicore fiber, the laser light propagates through the core group in a super mode representing propagation mode of the core group.

Abstract: An optical fiber bundle structure includes: a plurality of optical fiber core wires; and a capillary, wherein each of the optical fiber core wires includes a glass fiber portion including a core and a clad, and a resin coated portion, the glass fiber portions are inserted in the capillary, and d2/d1 is equal to or larger than 0.57 and smaller than 1, where d1 is a diameter of the core of each of the glass fiber portions in a rear end portion of the capillary and d2 is a diameter of the core of each of the glass fiber portions in a distal end portion of the capillary.

Abstract: A light source includes: a seed light source configured to output incoherent seed light with a predetermined bandwidth; and a booster amplifier that is a semiconductor optical amplifier configured to optically amplify the seed light input from a first facet, and output the amplified seed light as amplified light from a second facet, wherein the first facet and the second facet of the booster amplifier are subjected to a reflection reduction treatment, the booster amplifier is configured to operate in a gain saturated state, and relative intensity noise (RIN) and ripple are simultaneously suppressed in the amplified light.

Abstract: An optical amplifying fiber includes: at least one core portion including a rare earth element added therein; an inner cladding portion surrounding the at least one core portion, the inner cladding portion having a refractive index lower than a maximum refractive index of the at least one core portion; and an outer cladding portion surrounding the inner cladding portion, the outer cladding portion having a refractive index lower than the refractive index of the inner cladding portion, the inner cladding portion including different refractive index regions each having a refractive index different from a refractive index of a region adjacent to that different refractive index region.

Abstract: An optical fiber amplification. system includes: a first optical fiber amplifier including a first optical amplifying fiber including a core portion doped with a first rare-earth. element, a first input unit configured to receive first signal light, an excitation-light source configured to output pump light, a pump light combiner configured to input the pump light to the first optical amplifying fiber, and a residual pump light recovery device configured to recover residual pump light; and a second optical fiber amplifier including a second optical amplifying fiber including a core portion doped with a second rare-earth. element, a second input unit configured to receive second signal light, and a residual pump light combiner configured to input, to the second optical amplifying fiber, the residual pump light recovered by the residual pump light recovery device.

Abstract: A multi-core optical amplifying fiber includes: core portions doped with a rare-earth element; an inner cladding portion; and an outer cladding portion. A mode field diameter of each core portion at a wavelength at which the rare-earth element performs optical amplification is 5 ?m to 11 ?m, a relative refractive-index difference of the maximum refractive index of each core portion with respect to the inner cladding portion is 0.35% to 2%, a core-to-core distance is set such that total inter-core crosstalk is ?40 dB/100 m or lower in an optical amplification wavelength band subjected to the optical amplification, a cladding thickness is smaller than a value obtained by adding the mode field diameter to a minimum value of the core-to-core distance, and a ratio of a total sectional area of the core portions to a sectional area of the inner cladding portion is 1.9% or more.

Abstract: An optical amplifying fiber includes: at least one single core portion doped with a rare-earth element; an inner cladding portion configured to enclose the at least one core portion, the inner cladding portion having a lower refractive index than maximum refractive index of each core portion; and an outer cladding portion configured to enclose the inner cladding portion, the outer cladding portion having a lower refractive index than refractive index of the inner cladding portion, wherein the inner cladding portion includes a plurality of air bubbles.

Abstract: A cable comprising: a plurality of optical fiber cores; and one or more optical fiber core wires including one or more of the optical fiber cores. Further, at least one of the optical fiber core wire is fixed at a plurality of positions in a longitudinal direction of the cable so as to achieve substantially no displacement in a cable radial direction, at least a pair of the optical fiber core wires are fixed in a plane perpendicular to the longitudinal direction of the cable so as to achieve substantially no displacement relative to each other, and sensing of a strain profile in the longitudinal direction of at least the pair of the optical fiber core wires leads to achievement of sensing of a shape of the cable in the longitudinal direction.

Abstract: An optical fiber bundle structure includes: plural optical fiber core wires; a crossing preventing member; and a grasping member. Further, the crossing preventing member has slits and the widths of the slits positioned at the respective sides are each equal to or larger than a difference between: a length of one side of a polygon circumscribing the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of one side of a polygon circumscribing the plural optical fiber core wires at the leading end.

Abstract: An aim is to provide an optical coupler that contributes increasing pump-efficiency in an optical amplifier, and the optical amplifier.

Abstract: To provide an optical probe capable of changing a traveling direction of an output beam to a sideward direction. The optical probe includes an optical fiber that outputs a beam from a distal end thereof, and a traveling direction changing unit that changes a traveling direction of the output beam to a sideward direction with respect to the optical fiber. The optical probe includes a holder member that is mounted on a distal end side of the optical fiber and holds the optical fiber, and the traveling direction changing unit may be a reflector that is arranged on the holder member and that reflects output beam.

Abstract: A cable comprising: a plurality of optical fiber cores; and one or more optical fiber core wires including one or more of the optical fiber cores. Further, at least one of the optical fiber core wire is fixed at a plurality of positions in a longitudinal direction of the cable so as to achieve substantially no displacement in a cable radial direction, at least a pair of the optical fiber core wires are fixed in a plane perpendicular to the longitudinal direction of the cable so as to achieve substantially no displacement relative to each other, and sensing of a strain profile in the longitudinal direction of at least the pair of the optical fiber core wires leads to achievement of sensing of a shape of the cable in the longitudinal direction.

Abstract: An optical amplifier includes: a pump-light source unit outputting pump light beams having respective phases modulated; a polarization multiplexer/demultiplexer having first, second, and third ports, demultiplexing a light beam, input from the first port, into polarization components and outputting the demultiplexed light components from the second port and the third port; a first polarization-sensitive optical amplifying fiber unit connected to the second port of the polarization multiplexer/demultiplexer; a second polarization-sensitive optical amplifying fiber unit connected to the third port of the polarization multiplexer/demultiplexer; optical multiplexers/demultiplexers connected to the first polarization-sensitive optical amplifying fiber unit and the second polarization-sensitive optical amplifying fiber unit, respectively; an optical discharge unit, connected between the first polarization-sensitive optical amplifying fiber unit and the second polarization-sensitive optical amplifying fiber unit, di

Abstract: An aim is to provide an optical coupler that contributes increasing pump-efficiency in an optical amplifier, and the optical amplifier.

Abstract: An optical amplifier includes: a pump-light source unit outputting pump light beams having respective phases modulated; a polarization multiplexer/demultiplexer having first, second, and third ports, demultiplexing a light beam, input from the first port, into polarization components and outputting the demultiplexed light components from the second port and the third port; a first polarization-sensitive optical amplifying fiber unit connected to the second port of the polarization multiplexer/demultiplexer; a second polarization-sensitive optical amplifying fiber unit connected to the third port of the polarization multiplexer/demultiplexer; optical multiplexers/demultiplexers connected to the first polarization-sensitive optical amplifying fiber unit and the second polarization-sensitive optical amplifying fiber unit, respectively; an optical discharge unit, connected between the first polarization-sensitive optical amplifying fiber unit and the second polarization-sensitive optical amplifying fiber unit, di

Abstract: An optical amplifier includes: an optical amplifying fiber; and a pump light source that supplies pump light to the optical amplifying fiber, the pump light being used for parametrically amplifying signal light input to the optical amplifying fiber by using a non-linear optical effect of the optical amplifying fiber. The fluctuation of the zero-dispersion wavelength of the optical amplifying fiber in the longitudinal direction is within the limit of 0.5 nm/100 m.

Abstract: A multi-core optical amplifying fiber device includes a plurality of multi-core optical amplifying fibers including a plurality of core portions doped with amplification medium and a cladding portion formed at outer peripheries of the plurality of core portions; and a connection portion connecting the core portions of the plurality of multi-core optical amplifying fibers to one another. The connection portion connects the core portions to restrain deviation, between every connected core portions, of amplification gain for a total length of the core portions connected one another.