Fujikura Limited

Masashi Ikeda

Kuniharu Himeno

Masakazu Nakayama

Daiichiro Tanaka

Masaaki Ohtsuka

Masakazu Oohashi

Ning Guan

Kazuhiko Aikawa

Koichi Harada

Michihiro Nakai

Tomoharu Kitabayashi

Naritoshi Yamada

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.

Rare earth-doped core optical fiber and manufacturing method thereof

An optical fiber that includes a core containing a first concentration of germanium, an inner cladding arranged on the core, the inner cladding containing a second concentration of germanium and having a first diffusion coefficient, and an outer cladding arranged on the inner cladding, the outer cladding having a second diffusion coefficient, where the first diffusion coefficient is larger than the second diffusion coefficient, and where the first concentration of germanium is about 200% or more of the second concentration of germanium. An optical fiber constructed in this manner can be spliced with an optical fiber having a different MFD, such as a single-mode optical fiber or an erbium-doped optical fiber, with low splice loss and a sufficient splicing strength.

Optical fiber and optical fiber coupler, erbium-doped optical fiber amplifier, and optical waveguide using the same

A higher order mode dispersion compensating fiber includes an optical fiber and a first loss layer which is provided within the fiber and which attenuates a lower order mode propagating through the optical fiber while not attenuating a higher order mode which is higher than the lower order mode. A dispersion compensating fiber mode converter for a higher order fiber includes a single mode fiber; a higher order mode dispersion compensating fiber; and a fused and extended portion which has been formed by fusing and extending the single mode fiber and the higher order mode fiber. The fused and extended portion converts between the LPmode of the single mode fiber and the LPmode of the higher order mode dispersion compensating fiber.

Higher order mode dispersion compensating fiber and mode converter for higher order fiber

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Sakura, Japan

Masashi Ikeda