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Michihiro Nakai, Sakura-Shi JP

Michihiro Nakai, Sakura-Shi JP

Patent application numberDescriptionPublished
20090175575MULTIMODE OPTICAL COUPLER - A multi-mode optical coupler which includes an integrated section in which two optical fibers are fused and integrated together, at least one of these optical fibers being a multi-mode fiber, the multi-mode optical coupler coupling multi-mode light carried in the one of the multi-mode fibers to the other of the optical fibers, wherein: assuming that an outline of the integrated section in a plane view of the optical coupler is a function of a position along the longitudinal direction of the fibers, the multi-mode optical coupler has a plurality of inflection points along the outline; the multi-mode optical coupler satisfies: in an area between the farthermost inflection points includes: the length of the area between the inflection points is not more than 2 mm and an outer diameter h07-09-2009
20090274175FIBER LASER - This fiber laser is provided with: a signal light source that outputs a signal light; a rare earth-doped fiber that amplifies and outputs the signal light from the signal light source; a Raman amplifying fiber that is routed as a portion of an optical transmission path in order to output the output light from the rare earth-doped fiber to an outside thereof; and a wavelength selecting element that is provided in the optical transmission path from the Raman amplifying fiber to the signal light source and does not allow transmission of a Stokes light that is generated in the Raman amplifying fiber.11-05-2009
20090317042RARE EARTH-DOPED CORE OPTICAL FIBER AND MANUFACTURING METHOD THEREOF - A rare earth-doped core optical fiber of the present invention includes a core comprising a silica glass containing at least aluminum and ytterbium, and a clad provided around the core and comprising a silica glass having a lower refraction index than that of the core, wherein the core has an aluminum concentration of 2% by mass or more, and ytterbium is doped into the core at such a concentration that the light absorption band which appears around a wavelength of 976 nm in the light absorption band by ytterbium contained in the core shows a peak light absorption rate of 800 dB/m or less.12-24-2009
20100067860RARE EARTH-DOPED CORE OPTICAL FIBER - A rare earth-doped core optical fiber includes a core comprising a silica glass containing at least aluminum and ytterbium, a clad provided around the core and comprising a silica glass having a lower refraction index than that of the core, and a polymer layer provided on the outer circumference of the clad and having a lower refractive index than that of the clad, wherein aluminum and ytterbium are doped into the core such that a loss increase by photodarkening, T03-18-2010
20100097689OPTICAL AMPLIFIER, FIBER LASER, AND METHOD OF ELIMINATING REFLECTED LIGHT - A MO-PA type optical amplifier is provided which includes an oscillator and an amplifier including a fiber for optical amplification, including: a reflected-light wavelength conversion fiber which is provided on an optical path between the oscillator and the amplifier and which converts a wavelength of reflected-light traveling toward the oscillator due to Stimulated Raman Scattering; and a filter which is provided on the optical path between the oscillator and the amplifier and which eliminates the wavelength-converted light.04-22-2010
20100118897MULTI-CORE FIBER FOR OPTICAL PUMPING DEVICE AND MANUFACTURING METHOD THEREOF, OPTICAL PUMPING DEVICE, FIBER LASER AND FIBER AMPLIFIER - A multi-core fiber for an optical pumping device is provided. The multi-core fiber includes a plurality of optical fibers that are inserted into holes of an alignment member. The optical fibers and the alignment member are integrated by heating. The alignment member includes a material that has a lower softening temperature than a softening temperature of the optical fibers.05-13-2010
20100276822RARE EARTH-DOPED CORE OPTICAL FIBER AND MANUFACTURING METHOD THEREOF - A rare earth-doped core optical fiber of the present invention includes a core comprising a silica glass containing at least aluminum and ytterbium, and a clad provided around the core and comprising a silica glass having a lower refraction index than that of the core, wherein the core has an aluminum concentration of 2% by mass or more, and ytterbium is doped into the core at such a concentration that the absorption band which appears around a wavelength of 976 nm in the absorption band by ytterbium contained in the core shows a peak absorption coefficient of 800 dB/m or less.11-04-2010
20100284429PULSED LIGHT GENERATOR AND PULSED FIBER LASER - A pulsed light generator of the invention includes: an excitation light source; a fiber grating into which excitation light from the excitation light source enters; a rare-earth doped optical fiber optically coupled with the fiber grating, in which a rare-earth element is doped into a core, serving as an optical transmitting section; an optical switch including a deflection element for causing a Q-switching operation; a first optical fiber that causes light from the rare-earth doped optical fiber to enter into the optical switch; and a second optical fiber for waveguiding pulsed light output from the optical switch. One surface side of the optical switch, into which light enters, is subjected to anti-reflection treatment with a reflectance with respect to a wavelength of the pulsed light output from the optical switch being 0.1% or less. A low-reflection section having a reflectance with respect to the wavelength of the pulsed light output from the optical switch of from 1% to 60% inclusive, is arranged on an other surface side of the optical switch, from which light is emitted.11-11-2010

Patent applications by Michihiro Nakai, Sakura-Shi JP