Mitsubishi Cable Industries, Ltd.

Nec Corporation

Yasuhide Sudo

Kazuo Imamura

Minoru Yoshida

Katsuaki Kondo

Tadahiko Nakai

Tatsuhiro Kawamura

Atsushi Toyohara

Takashi Okuyama

Hideki Okuno

Yoshiyuki Imada

The present invention includes a sheet material, a first optical fiber, a second optical fiber optically coupled to the first optical fiber in portions thereof, and an optical fiber coupler constituted in the portions where the two optical fibers are coupled, and those of the first and second optical fibers, and the optical fiber coupler are integrally held in the sheet material.

Optical fiber holding structure

A core is co-doped with Ge in a general concentration equivalent to that in a core of an optical fiber to be connected as well as Sn and Al in predetermined concentrations. A glass part F including the core and a cladding is coated with a primary coat layer of a UV transmitting resin which transmits UV of 240 nm through 270 nm but cures by absorbing UV of a shorter wavelength band than 240 nm or a longer wavelength band than 270 nm. A grating is written in the core by irradiating the core with UV through the primary coat layer. The primary coat layer is covered with a secondary coat layer of a resin having a negative coefficient of linear expansion so as to cancel and suppress expansion/shrinkage of the glass part in accordance with temperature change derived from the positive coefficient of linear expansion. Thus, the invention provides a fiber grating and a method of fabricating a fiber grating, in which a grating can be easily written without causing degradation of the transmitting characteristic, the transmitting characteristic and the mechanical strength characteristic can be consistent with each other without spoiling improvement of productivity, and the temperature characteristic can be stabilized for attaining high reliability.

Fiber grating and method and apparatus for fabricating the same

A long period grating ( ) by which an excitation light propagated through the 2nd core ( ) of a double-core type optical fiber composed of the 2nd core ( ) formed on the outer circumference of the 1st core ( ) is guided into the 1st core ( ) is formed on the 1st core ( ) to improve an excitation efficiency.

Optical fiber

A structure for retaining an optical fiber, capable of not only handling a long optical fiber as one piece without causing the optical fiber as a whole to get loose but also reducing an area occupied by the optical fiber and retaining the same stably without causing micro-bending thereof to occur, wherein the optical fiber ( ) is arranged so as to form planarly staggered turning portions thereof without causing intersecting parts to occur, a plurality of similar planarly staggered turning portions of the optical fiber being laminated in the same position in the direction of the thickness thereof which is at right angles to a plane on which the optical fiber is arranged, the resultant optical fiber ( ) being generally retained in a sheet-like state by a fixing material ( ), such as a bonding agent and a film.

Structure for retaining optical fiber

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Hyogo, Japan

Yasuhide Sudo