Abstract: A fiber laser system enables an improved reflection resistance property. The fiber laser system includes fiber lasers (2 through 4) each having a laser medium which is an optical fiber made from silica glass. A difference between respective lasing wavelengths of any given two of the fiber lasers is greater than a wavelength equivalent to a half width at half maximum of a peak deriving from a vibration mode of a planar four-membered ring of a Si—O network structure of silica glass.

Abstract: The light power monitoring device includes: a first optical fiber; a second optical fiber connected to the first optical fiber; a low-refractive-index resin layer which covers (i) a connection between the first and the second optical fibers and (ii) a predetermined region of the second optical fiber which region extends from the connection toward a forward-propagating-light-output side; a high-refractive-index resin layer which covers a region of the second optical fiber which region is not covered by the low-refractive-index resin layer; and an outputted light detecting device which is provided at a position corresponding to an end of the low-refractive-index resin layer which end is located on the forward-propagating-light-output side of the second optical fiber or at a position which is away toward the forward-propagating-light-output side of the second optical fiber from the position corresponding to the end of the low-refractive-index resin layer.

Abstract: The present invention achieves a fiber laser having a high reflection resistance. A length of an optical fiber MMF is set so that a condition is satisfied at each point on an individual optical path of a fiber laser (FL2), the condition being that a difference between time at which a power of a forward Stokes beam (SF) is at a maximum value and time at which a power of a backward Stokes beam (SB) is at a maximum value is greater than a sum of a half width at half maximum of the power of the forward Stokes beam (SF) and a half width at half maximum of the power of the backward Stokes beam (SB).

Abstract: Provided is an optical fiber including a low-refractive-index layer that is disposed between a first cladding and a second cladding and that has a refractive index between those of the first and second claddings. The first cladding has a cladding diameter that is 2.5 or more times the MFD of the fundamental mode at a fluorescence wavelength of an active element in a core, and the low-refractive-index layer has a thickness that is equal to or more than an absorption wavelength of the active element.

Abstract: In a fiber laser system (1) for outputting a laser beam obtained by combining a plurality of laser beams outputted by driving the respective fiber laser unit (2a, 2b, 2c), a control section (7) controls a plurality of current sources (6a, 6b, 6c) so that there are time intervals of a certain time between peaks which appear in a case where respective powers of the laser beams rise.

Abstract: A fiber laser system enables an improved reflection resistance property. The fiber laser system includes fiber lasers (2 through 4) each having a laser medium which is an optical fiber made from silica glass. A difference between respective lasing wavelengths of any given two of the fiber lasers is greater than a wavelength equivalent to a half width at half maximum of a peak deriving from a vibration mode of a planar four-membered ring of a Si—O network structure of silica glass.

Abstract: A fiber laser apparatus includes a pumping light source which launches pumping light, an amplifying optical fiber which includes a core and a noncircular cladding, and absorbs the pumping light to launch laser light, an amplifying coil which has a configuration around which the amplifying optical fiber is wound, a first reflector which is provided on an input side of the amplifying coil and is configured to reflect the laser light toward the amplifying coil, and a second reflector which is provided on a launching side of the amplifying coil, has a lower reflectance than a reflectance of the first reflector, and is configured to reflect the laser light toward the amplifying coil.

Abstract: An optical power monitor device includes a first optical fiber, including a core and a cladding surrounding the core and being at least one of an incidence-side optical fiber and a launch-side optical fiber connected to each other at a connection point, which is constituted by a curve portion and a linear portion between the curve portion and the connection point, a low refractive index layer that is provided in at least a portion of the linear portion on an outer side of the cladding and has a refractive index lower than a refractive index of the cladding, and a first optical detector that is provided at a position close to at least the curve portion.

Abstract: A fiber laser device (1) includes an amplification optical fiber (10) having a core (11) doped with an active element, a first FBG (35) reflecting at least a part of light emitted from the active element, and a second FBG (45) reflecting the light reflected off the first FBG (35) at a reflectance lower than the reflectance of the first FBG (35). The wavelength of a fundamental-mode light beam reflected off the first FBG (35) and the wavelength of a fundamental-mode light beam reflected off the second FBG (45) are matched with each other. The wavelengths of higher-mode light beams reflected off the first FBG (35) and the wavelengths of higher-mode light beams reflected off the second FBG are unmatched with each other.

Abstract: The purpose of the present invention is to provide a lightweight composite material structure while suppressing a drop in strength. In a composite material structure, which is configured as a fiber-reinforced plastic composite material extending in one direction and having a plurality of holes (5) formed at intervals in a row in the one direction and which is subjected to a tensile load and/or a compressive load in the one direction, a peripheral region (3a) around the holes (5) comprises a first area (10) obtained by bending composite material, which is reinforced using continuous fibers that have been made even in the longitudinal direction, so that the center line of the width (W) of the composite material weaves between adjacent holes (5) and zigzags in the one direction.

Abstract: There is provided a photonic bandgap fiber used in a state in which at least a part of the photonic bandgap fiber is bent at radii of 15 cm or greater and 25 cm or less. A large number of high refractive index portions 57 are disposed in a nineteen-cell core type in three layers, and a V value is 1.5 or greater and 1.63 or less. In the high refractive index portions 57, conditions are defined that a relative refractive index difference is ?% and a lattice constant is ? ?m so as to remove light in a higher mode at the bent portion as described above.

Abstract: An optical fiber 10 propagates a light beam at a predetermined wavelength at least in an LP01 mode and an LP02 mode. In regions 11a and 11c in which the intensity of a light beam in the LP02 mode is greater than the intensity of a light beam in the LP01 mode, at least a part of a Young's modulus in the region 11c on the circumferential side of the region 11b in the core in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode is smaller than a Young's modulus in the region 11b in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode.

Abstract: The light power monitoring device includes: a first optical fiber; a second optical fiber connected to the first optical fiber; a low-refractive-index resin layer which covers (i) a connection between the first and the second optical fibers and (ii) a predetermined region of the second optical fiber which region extends from the connection toward a forward-propagating-light-output side; a high-refractive-index resin layer which covers a region of the second optical fiber which region is not covered by the low-refractive-index resin layer; and an outputted light detecting device which is provided at a position corresponding to an end of the low-refractive-index resin layer which end is located on the forward-propagating-light-output side of the second optical fiber or at a position which is away toward the forward-propagating-light-output side of the second optical fiber from the position corresponding to the end of the low-refractive-index resin layer.

Abstract: A composite structure (3) formed of a composite member which extends in one direction, includes holes (5), and is made of fiber reinforced plastics. A tensile load and/or a compressive load are applied to the composite structure (3) in the one direction. Tensile stiffness and/or compression stiffness of peripheral areas (3a) of the holes (5) is lower than tensile stiffness and/or compression stiffness of the other area (3b), which surrounds the peripheral areas (3a), in the one direction, and the width of the peripheral area (3a) in a direction orthogonal to the one direction is set to 1.1 times or less of the diameter of the hole (5) in the direction orthogonal to the one direction.

Abstract: The refractive index of the first core portion 11a is higher than that of a clad 12, and the refractive index of the second core portion 11b is higher than that of the first core portion 11a. When light of the LP01 mode and light of the LP11 mode are standardized by power, in the core 11, an active element that stimulates to emit light of the predetermined wavelength is doped at a higher concentration in at least a part of an area where power of light of the LP01 mode is larger than that of light of the LP11 mode than at least a part of an area where the power of light of the LP11 mode is larger than that of light of the LP01 mode.

Abstract: An absorbent article package is individually packaged by folding a packaging sheet and an absorbent article in a state where the absorbent article is arranged on the packaging sheet. In a state where the individually-packaged absorbent article is opened, in the packaging sheet and the absorbent article, a first folding line based on which the absorbent article and the packaging sheet are folded towards the topsheet side, and a second folding line based on which the absorbent article and the packaging sheet are folded towards the backsheet side are formed adjacent to each other in the longitudinal direction.

Abstract: An optical fiber propagates a light beam at a predetermined wavelength at least in an LP01 mode and an LP02 mode. A dopant that changes a Young's modulus is doped to at least a part of a waveguide region 12a of a cladding 12 through which a light beam at a predetermined wavelength is propagated and to a region 11b in a core 11 in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode. At least a part of the Young's modulus in the waveguide region 12a of the cladding 12 is smaller than a Young's modulus in the region 11b in the core 11 in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode.

Abstract: The refractive index of the first core portion 11a is higher than that of a clad 12, and the refractive index of the second core portion 11b is higher than that of the first core portion 11a. When light of the LP01 mode and light of the LP11 mode are standardized by power, in the core 11, an active element that stimulates to emit light of the predetermined wavelength is doped at a higher concentration in at least a part of an area where power of light of the LP01 mode is larger than that of light of the LP11 mode than at least a part of an area where the power of light of the LP11 mode is larger than that of light of the LP01 mode.

Abstract: There is provided a photonic bandgap fiber used in a state in which at least a part of the photonic bandgap fiber is bent at radii of 15 cm or greater and 25 cm or less. A large number of high refractive index portions 57 are disposed in a nineteen-cell core type in three layers, and a V value is 1.5 or greater and 1.63 or less. In the high refractive index portions 57, conditions are defined that a relative refractive index difference is ?% and a lattice constant is ? ?m so as to remove light in a higher mode at the bent portion as described above.

Abstract: A solid photonic band gap fiber includes: a core area located at a central portion of a cross-section with respect to a longitudinal direction of the fiber, the core area being formed of a solid substance having a low refractive index; cladding areas having base portions formed of a solid substance having a low refractive index, the cladding areas surrounding the core area; and a plurality of fine high refractive index scatterers provided in the cladding areas, and disposed in a dispersed manner so as to surround the core area, the number of fine high refractive index scatterers being formed of a solid substance having a high refractive index, wherein in a state that the solid photonic band gap fiber is held at a predetermined bending radius, propagation in a high-order mode is suppressed by using a difference in a bending loss between a fundamental mode and the high-order mode, and only the fundamental mode is substantially propagated, the fundamental mode and the high-order mode being caused by bending.