Fujikura Limited

Hokkaido University

Panasonic Corporation

Masahiro Kashiwagi

Kunimasa Saitoh

Hiroyuki Kusaka

Kensuke Shima

Kazuhisa Yamamoto

Hiroyuki Furuya

Katsuhiro Takenaga

Kuniharu Himeno

Shinichi Kadowaki

Shoji Tanigawa

Ryuichiro Goto

Toshio Mouri

Tomoya Ichige

An optical amplification apparatus includes a first amplification optical fiber, a second amplification optical fiber, a first pumping light source, and a second pumping light source. The first amplification optical fiber includes a first core and a first cladding layer. The first core is doped with an active element using a first active element doping concentration distribution. The first cladding layer is disposed out of the first core and has a refractive index lower than the refractive index of the first core. The second amplification optical fiber is connected to the first amplification optical fiber in a longitudinal direction of the first amplification optical fiber. The second amplification optical fiber includes a second core and a second cladding layer. The second core is doped with active element using a second active element doping concentration distribution that is different from the first active element doping concentration distribution.

Optical amplification apparatus

A fiber laser apparatus includes a pump light source that emits pump light; a pump delivery fiber that guides the pump light; an amplifying optical fiber that is optically coupled to the pump delivery fiber and guides laser light; and a filter element that causes more loss of light of a wavelength range that includes a peak wavelength of at least one of Stokes light and anti-Stokes light than the laser light. The Stokes light and anti-Stokes light result from four-wave mixing involving a plurality of guide modes in a multi-mode fiber that guides the laser light. The filter element is disposed between: the pump delivery fiber and the amplifying optical fiber, the amplifying optical fiber and the multi-mode fiber, or at the multi-mode fiber.

Filter element, laser device, fiber laser device, filter method, and method for manufacturing laser device

An optical devicehas a GRIN lens, a preceding-stage optical fiberfrom which a light beam is entered to the GRIN lens, and a subsequent-stage optical fiberto which a light beam emitted from the GRIN lensis entered. A method for adjusting beam quality includes a measurement process Pin which a light beam is entered to the preceding-stage optical fiberand the beam quality of a light beam to be emitted from the subsequent-stage optical fiberthrough the GRIN lensis measured, and an adjustment process Pin which the length of the GRIN lensis adjusted on the basis of a result in the measurement process P

Method for manufacturing optical device, method for manufacturing laser device, method for adjusting beam quality of laser device

In a case where a variation in reflection resistance among fiber lasers occurs, a reflection resistance of a fiber laser system as a whole is restored by reducing the variation while maintaining an output power of the fiber laser system as a whole. The fiber laser system includes a control section (C) configured to increase a proportion of a backward excitation power (PBi) in a fiber laser (FLi) so that fiber lasers (FLthrough FLn) less vary in reflection resistance.

Fiber laser system and method for controlling same

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.

Optical power monitor device and optical power monitor method

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.

Fiber laser apparatus and method of manufacturing amplifying coil

Reflection resistances of respective fiber lasers in a state where an entire fiber laser system is in operation are evaluated. Each of fiber lasers (through) includes (i) a laser beam measuring section () configured to measure a power of a laser beam which a low reflection FBG () has transmitted therethrough and (ii) a Stokes beam measuring section () configured to measure a power of a Stokes beam which a high reflection FBG () has transmitted therethrough.

Fiber laser system, reflection resistance evaluation method and reflection resistance improvement method for same, and fiber laser

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 (FL), 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).

Fiber laser system, fiber laser system production method, and processing method

In a fiber laser system () for outputting a laser beam obtained by combining a plurality of laser beams outputted by driving the respective fiber laser unit (), a control section () controls a plurality of current sources () 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.

Fiber laser system and method of outputting laser beam

A bridge fiber includes a core layer and an outer layer which has an index of refraction higher than that of the core layer and covers the outer peripheral surface of the core layer. The outer layer is surrounded by a substance such as the atmosphere having an index of refraction lower than an index of refraction nof the outer layer. An area ARof the outer layer at one end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of each of a plurality of pumping light inputting optical fibers, while an area ARof the core layer at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber.

Bridge fiber, combiner, and fiber laser device

A fiber laser system enables an improved reflection resistance property. The fiber laser system includes fiber lasers (through) 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&#x2014;O network structure of silica glass.

Fiber laser system

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.

Optical-power monitoring device, fiber laser, and optical-power monitoring method having different regions of a second fiber covered by a low-refractive-index resin layer and a high-refractive-index resin layer

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 portionsare 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, conditions are defined that a relative refractive index difference is &#x394;% and a lattice constant is &#x39b; &#x3bc;m so as to remove light in a higher mode at the bent portion as described above.

Photonic bandgap fiber and fiber laser device using same

An optical fiberpropagates a light beam at a predetermined wavelength at least in an LPmode and an LPmode. In regionsandin which the intensity of a light beam in the LPmode is greater than the intensity of a light beam in the LPmode, at least a part of a Young's modulus in the regionon the circumferential side of the regionin the core in which the intensity of the light beam in the LPmode is greater than the intensity of the light beam in the LPmode is smaller than a Young's modulus in the regionin which the intensity of the light beam in the LPmode is greater than the intensity of the light beam in the LPmode.

Optical fiber and fiber laser device using same

The refractive index of the first core portionis higher than that of a clad, and the refractive index of the second core portionis higher than that of the first core portion. When light of the LP01 mode and light of the LP11 mode are standardized by power, in the core, 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.

Growing community of inventors

Sakura, Japan

Masahiro Kashiwagi