Kokusai Denshin Denwa Kabushiki Kaisha

Kokusai Denshin Denwa Co., Ltd.

Makoto Nunokawa

Yoshihiro Ejiri

Hitoshi Yamamoto

Kahei Furusawa

Taiichiro Nakai

Yasuhiko Niiro

Yoshihiko Yamazaki

Masanori Sato

Koichi Tatekura

Hiroharu Wakabayashi

Yoshinao Iwamoto

Yukio Nakagome

Kiyofumi Mochizuki

Kitsutaro Amano

Yoshinori Namihira

Hiroshi Yuguchi

An optical fiber cable in which at least those metallic members of the optical fiber cable which are of high chemical reactivity and electrochemical reactivity are each precoated with a film for preventing them from making direct contact with water when it diffuses into the cable. The film may be a nonmetallic film or a metallic film of low chemical reactivity and electrochemical reactivity.

Optical fiber cable

In the connection of the opposed ends of two optical fibers, a method and apparatus for core alignment of the optical fibers, comprises placing the two optical fibers being connected so that their ends face each other, and illuminating at least the facing ends with a beam of ultraviolet light thereby causing the illuminated ends of the cores of the optical fibers which are doped with germanium (Ge) to emit light of a wavelength in the visible region and enabling the core alignment to be directly monitored visually with the aid of the visible light so emitted from the cores during the course of the core alignment.

Method and apparatus for core alignment of optical fibers

A spliced portion housing structure for an optical fiber in an optical submerged repeater, characterized in that, in order to splice together in a joint ring an optical fiber and a power-supplying feeder from the optical submerged repeater to an optical fiber and a power-supplying feeder of a tail cable from a cable coupling of an optical submarine cable, respectively, a joint chamber is provided on an end plate of a housing of the optical submerged repeater in such a manner that the end plate forms a part of the joint chamber; the optical fiber and the power-supplying feeder from the submerged repeater are introduced into the joint chamber through a first feedthrough provided in the end plate for hermetically introducing the optical fiber and the power-supplying feeder; the tail cable from the cable coupling is hermetically introduced into the joint chamber through a second feedthrough provided in the wall of the joint chamber so that the tail cable is insulated from the joint chamber, the optical fibers and the feeders pulled into the joint chamber from both of the first and second feedthroughs are respectively spliced together while being isolated from each other and housed in the joint chamber; the optical fiber spliced portion is fixed to a cage mounted in the joint chamber; and the joint chamber is formed to have a water pressure resisting and airtight structure.

Spliced portion housing structure for optical fiber in optical submerged

An optical fiber submarine cable, which is provided with at least one coated optical fiber, a power supplying, pressure resisting layer of a pipe-like configuration, a tension resisting wire layer formed of a conductive material of relatively low conductivity and disposed in close contact with the power supplying, pressure resisting layer of the pipe-like configuration, and an insulator layer disposed around the tension resisting wire layer. The power supplying, pressure resisting layer is formed as at least one inner layer and an outer layer. The inner layer is formed as a single layer or composite layers by forming a tape-like good conductor material into a pipe-like configuration with its joint made a mere butt, or by assembling together a plurality of pressure resisting material segments equally divided in the circumference direction for at least one layer of the inner layer and having housed the above-mentioned at least one coated optical fiber in an optical fiber housing space defined centrally of the inner layer. The outer layer is formed by winding a metal tape on the inner layer.

Optical fiber submarine cable

An optical fiber unit for optical submarine cables, in which glass portions formed by a plurality of optical fibers each having at least one coating layer and twisted together at a required pitch are embedded in a resin layer. Adjacent two layers of the coating layer and the resin layer are formed of the same material or materials which satisfy the following condition; ##EQU1## where E.sub.1 is the Young's modulus of the inner one of the two layers, E.sub.2 is the Young's modulus of the outer one of the two layers, .nu..sub.1 is the Poisson's ratio of the inner one of the two layers and .nu..sub.2 is the Poisson's ratio of the outer one of the two layers, the thus coated portion being formed over the entire length of the optical fibers or at desired intervals.

Optical fiber unit for optical submarine cables

An optical fiber submarine cable comprising at least one optical fiber. A pipe-like pressure resisting layer is produced by forming a tape-like pressure resisting material into a pipe-like configuration with the optical fiber inserted therein. The pressure resisting layer has butt ends in its cross section, and a waterproof insulator layer is disposed closely around the pipe-like pressure resisting layer for maintaining the pipe-like configuration of the pipe-like pressure resisting layer and for preventing seawater from entering into a gap between the butt ends.

An optical fiber submarine cable, in which a high viscosity material of good wettability containing air gaps is filled in a space between an optical fiber cord having housed therein at least one coated optical fiber and a pressure resisting material layer having housed therein the optical fiber cord for protecting it from seawater pressure. The air gaps and the high viscosity material are arranged alternately with each other in the space at suitable intervals in the lengthwise direction of the cable. Alternatively, the air gaps are contained in the form of bubbles in the high viscosity material.

An optical-fiber submarine cable, in which a combination is provided by a thin, cylindrical pressure resisting sheath, and a reinforcing member of a cross section inserted by the thin, cylindrical pressure resisting sheath so as to divide the circular cross section of the pressure resisting sheath into a plurality of spaces and to have a required withstand pressure; and in which at least one low-loss optical fiber is inserted in each of the plurality of spaces. The combination can be fabricated by separately paying out the reinforcing member and the thin, cylindrical pressure resisting sheath, or by curving inwardly a sheet of tape being paid out.

Optical-fiber submarine cable and manufacturing method thereof

A frequency band compression method, using Time Compression, for use with a frequency division multiplex (FDM) signal carrying voice signal. On the transmission end, the multiplexed signal is divided into a plurality of time segments, each segment having a certain duration, then deleting a part of the each segment and time-expanding the remaining part of the segment by a sawtooth variable delay, thus lowering the frequency of the signal to a predetermined ratio. On the receive end, the signal segments are compressed by a corresponding variable delay, thus making the received frequency higher and reproducing the original multiplexed voice signals.

Growing community of inventors

Kawasaki, Japan

Makoto Nunokawa