Fujikura Limited

Hiroshi Hidaka

Osamu Fukuda

Koichi Takahashi

Masahiro Sato

Takao Shiota

Ryozo Yamauchi

Michihiro Nakai

Tetsuya Sakai

Akira Wada

Satoshi Okude

Kensuke Shima

Koichi Inada

Masaaki Sudoh

Kuniharu Himeno

Ryokichi Matsumoto

Kenji Nishide

Shigefumi Yamasaki

Hideki Sasaki

Takuya Ienaka

Yoji Suzuki

In a method of manufacturing a polarization-maintaining optical fiber coupler by heating lengthwise portions of two polarization-maintaining optical fibers extending side by side, and elongating the heated portions to thereby form a fused-elongated section, elongation is terminated when the cyclic changes in a coupling ratio of two polarized waves according to an elongation length at a wavelength in use are both within first two cycles, so that the coupling ratio of one of the polarized waves is equal to or less than 10% and the coupling ratio of the other one of the polarized waves is equal to or greater than 90%. This method can provide a polarization-maintaining optical fiber coupler whose coupling ratio has a large dependency on polarization with a short elongation length.

Method of manufacturing polarization-maintaining optical fiber coupler

An optical waveguide grating with radiative mode-coupling properties, with exceptional stability and reliability as an optical component, wherein the central wavelength of the rejection band has a low temperature dependence, due to the use of silica glass doped with germanium and boron for the core. The rejection bandwidth can be narrowed without increasing the grating length by forming the radiative mode-coupled optical waveguide grating in an optical waveguide wherein the mean relative refractive index difference of the core is greater than that of optical communication waveguides. The rejection can be increased by reducing the occurrence of cases wherein propagation modes of the core coupled to cladding modes once again couple to the core in palnar optical waveguide gratings formed by making periodic changes in the waveguide structure along the direction of propagation of light in an optical waveguide having a cladding with a lower refractive index than the core surrounding the core, by making the thickness of the cladding at least thirteen times the thickness of the core.

Optical waveguide grating and production method therefor

Core comprises a main stem which is formed on a substrate, linearly extending in the beam propagating direction and short branches with a certain length which extend perpendicularly to the beam propagating direction toward both sides along the plane of the substrate and are arranged at regular intervals in the beam propagating direction. Thus, the branches are arranged in a ladder geometry when it is viewed from the top, forming a rectangular waveform arrangement. The core constitutes a grating structure in which the width of the core is made to vary periodically with the branches in the beam propagating direction.

Optical filter with planar optical waveguide having periodically varied

A device for fabricating an oxide superconductor cable includes a spinning furnace for receiving a preform and spinning the preform into a glass fiber. The device further includes a sputtering apparatus for receiving the spun glass fiber and coating the glass fiber with an oxide superconductor film as well as a pulling mechanism for pulling the glass fiber.

Apparatus for producing oxide superconductor cable

An oxide superconductor cable and a method of producing the same. The oxide superconductor cable includes a ceramic fiber and an oxide superconductor layer coated over the ceramic fiber. Such a structure of the cable provides flexibility to it to some extent and enables it to become relatively thin.

Oxide superconductor cable and method of producing the same

A single crystal oxide superconductor and the method of producing the same. One face of a substrate is coated with an oxide superconductor for forming an oxide superconductor layer. Then, the oxide superconductor layer is heated so that the oxide superconductor has a single crystalline structure.

Single crystal oxide superconductor and method of producing the same

An oxide superconductor including an oxide superconductor member and a hermetical seal layer, coated over the oxide superconductor member, for hermetically sealing the oxide superconductor member from the atmosphere.

Oxide superconductor

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Tsukuba, Japan

Hiroshi Hidaka