Mitsubishi Cable Industries, Ltd.

Nippon Telegraph and Telephone Corporation

Moriyuki Fujita

Satoki Kawanishi

Masatoshi Tanaka

Hirokazu Kubota

Kazunori Suzuki

Kenji Sato

Takeshi Satake

Motohiko Yamasaki

Yoshiki Yamakawa

Mamoru Nakamura

A 1.55 &#x3bc;m band dispersion shifted optical fiber is provided which has a low loss and low dispersion slope. A core region 'a' is heavily doped with GeO. A core region 'b' is composed of pure SiOglass. A cladding section is arranged around the core region. The cladding section has a lot of holes extending in the longitudinal direction of the optical fiber. The holes of the cladding section are not located at random, but have a honeycomb structure composed of regular hexagons which have a side length of &#x39b;, and serve as a primitive lattice. The center of the core section has a region having a refractive index higher than that of the periphery of the core section. The core section has the refractive index distribution in which the group velocity dispersion at the operation wavelength of the region becomes the normal dispersion.

Dispersion shifted optical fiber

An optical fiber/glass tube fusion spliced structure includes an optical fiber made of glass and a glass tube through which the optical fiber is inserted and at least in part of the optical fiber/glass tube fusion spliced structure, an outer circumference portion of the optical fiber and an inner circumference portion of the glass tube are fusion spliced. Part of the fusion spliced portion located in one of the optical fiber and the glass tube is formed of a material having a lower fusion point than a fusion point of part of the fusion spliced portion located in the other.

Optical fiber/glass tube fusion-spliced structure, optical fiber assembly including the structure, and glass tube used in the structure

A polarization-maintaining optical fiber and absolutely single-polarization optical fiber are provided which enable long distance transmission maintaining a polarization state of signal light. The polarization-maintaining optical fiber includes a core, photonic crystal cladding, and jacket. The photonic crystal cladding is divided into four segments by broken lines from the center to the periphery. Among a plurality of grating holes in a pair of segments opposed to each other with respect to the core, the diameter of grating holes close to the core is greater than the diameter of grating holes in another pair of segments opposed with each other, and than a grating constant.

Polarization preserving optical fiber and absolute single polarization optical fiber

Growing community of inventors

Itami, Japan

Moriyuki Fujita