Kokusai Denshin Denwa Co., Ltd.

Other

Kokusai Denshin Denwa Kabushiki Kaisha

Duo-Fast Corporation

Kdd Corporation

Kdd Submarine Cable Systems, Inc.

Kakusai Denshin Denwa Kabushiki Kaisha Et Al.

Kenichi Asakawa

Yoshinao Iwamoto

Yuichi Shirasaki

Kazuomi Yamamura

Hideo Ishihara

Shizuo Suzuki

Masayuki Fujise

Yuichi Sirasaki

Junichi Kojima

Koji Goto

Kazunori Sato

Toshio Kawazawa

Eiichi Nakagawa

Hitoshi Nishikawa

Satoru Takagi

Satoshi Kumayasu

Toshio Izawa

Naoki Norimatsu

Hifumi Sakaguchi

Koh-ichi Tatekura

Etsuo Nazuka

A feed line switching circuit includes a relay connected between feed lines, a normally close contact of the relay, and a resistor that constitutes a series circuit with the normally close contact, which series circuit is connected in parallel with the relay. The resistance of the coil of the relay and the resistance of the resistor are determined to satisfy the condition that the current flowing through the relay after energizing the relay can prevent the chattering of the relay. Thus, the feed line switching circuit can positively carry out the feed line switching.

Feed line switching circuit and branching unit

A feed line connecting circuit for selectively connecting first, second and third feed line connecting terminals under a predetermined current feeding condition comprises a first current detector connected between one of the first and second feed line connecting terminals and a central node for detecting a current over a predetermined value; a first switch connected between the one of the first and second feed line connecting terminals and the central node for connecting said one of the first and second feed line connecting terminals to the central node under an unpowered condition; a selective switch controlled by the first current detector, the selective switch having first and second contacts and a common contact connected to the third feed line connecting terminal, the common contact being connected to the first selective contact when the first current detector does not detect a current over the predetermined value, and to the second selective contact when the first current detector detects a current over the predetermined value; and a second current detector connected between the first selective contact of the selective switch and the central node to change the first switch so as to disconnect said one of the first and second feed line connecting terminals from the central node when detecting a current above the predetermined value.

Feed line connection circuit and optical transmission system

When a trouble occurs in a cable, a feeding pass for another cable is ensured. In a feeding pass switching circuit, optical fibers are respectively connected to the terminals A, B and C. When a negative current is applied to the system in a state where a BRANCH2 is put in an open circuit and a TRUNK is grounded, a relay K1 is activated, and then a relay K2 is activated. Successively, when a positive current is supplied from the TRUNK, a cable connected to the TRUNK and a BRANCH1 is fed from both terminals. When the positive current is supplied from the BRANCH1 in a state where the TRUNK is put in a open circuit and the BRANCH2 is grounded, a relay K3 is activated. Successively, when the negative current is supplied to the BRANCH2, a relay K5 is activated. In such a manner, the power is fed to each feeding pass from one terminal.

Feeding pass switching circuit

A remotely operated submersible robot 10 is provided with two differential triaxial orthogonal dc magnetic sensing units, 1 and 2, each comprising two triaxial orthogonal dc magnetic sensors spaced at a predetermined distance apart and with their corresponding axes set in parallel; each triaxial orthogonal dc magnetic sensor incorporating three dc magnetic sensing elements sensitive only to a magnetic field in a specific axial direction and disposed such that the axial directions of respective dc magnetic sensing elements cross each other at right angles. Analog signals sent out from the differential triaxial orthogonal dc magnetic sensing units 1 and 2 are converted into digital signals by an analog-to-digital converter, and transmitted to a mother ship 20 via a tether cable 6. The output signals thus transmitted from the aforesaid sensing units are processed by a processing unit installed in the mother ship 20 to compute the distance to a submarine cable, a difference in elevation between the submarine cable and the submersible robot, and the direction of the submarine cable laid down, which are shown on a display.

Maritime apparatus for locating a buried submarine cable

A core alignment system for aligning a pair of optical fibers to be spliced, in which core alignment is accomplished by applying a pair of aligned beams of light emitted in opposite directions by a semiconductor laser to the butt joint ends of a pair of optical fibers to be spliced, detecting a leakage beam leaking from a side surface of each optical fiber close to the laser, and adjusting the positioning of the optical fibers so that the leakage beams are minimized.

Core alignment system for optical fibers

A device for burying a submarine cable under water by easily and accurately detecting the cable position and a method for guiding the same by utilizing the characteristics unique to submarine cables, by supplying an AC only to the portion of the cable between two arbitrary repeaters through a so-called transformer-coupling system to generate an AC magnetic field, and by detecting the magnetic field with a magnetic field detector.

Burying device for submarine cables and method for guiding the same

A rotary joint for optical fibers consists of two rotary members which enable efficient transmission of optical signals without the need of converting the same into electric signals by attaching rod lenses having a refractive index in the second order distribution relative to its center axis, to respective tips of the optical fibers capable of relative rotation so that an optical signal emitted from the tip of one optical fiber is transmitted from the end of one rod lens in the form of parallel rays to the other rod lens, and as a converged beam to the tip of the other optical fiber. The joint further includes a mechanism for imparting pressure to the rotary members, and a mechanism for finely setting the angle between the two rod lenses.

Rotary joint for optical fibers

This invention aims to provide an optical fiber which is capable of sufficiently dissipating the leaky mode in the cladding thereof characterizing in those particulate substances such as minute hollow glass beads having different refractive indices are sealed in the primary buffer layer or on the boundary between the primary buffer layer and the cladding, or between the primary and secondary buffer layers of the optical fiber, whereby nucleous elements for scattering or absorption can be formed uniformly.

Optical fiber with light reflecting particles dispersed through buffer

A device for burying a submarine cable under water by easily and accurately directing the cable position and a method for guiding the same by utilizing the characteristics unique to submarine cables, by supplying an AC only to the portion of the cable between two arbitrary repeaters through a so-called transformer-coupling system to generate an AC magnetic field, and by detecting the magnetic field with a magnetic field detector.

Apparatus for supplying AC current to an underwater cable

A connector for connecting together in a water-tight housing various optical instruments of an underwater or submarine arrangement having optical fiber cables. The connector is constructed in a manner such that a plug containing the terminals of optical fiber cables is connected in an easily attachable/detachable fashion to a receptacle which is mounted on the water-tight housing. Sealing material is interposed between the water-tight housing and the receptacle and between the receptacle and the plug for preventing the infiltration of water or sea water into the water-tight housing.

Underwater optical fiber connector

A device for burying a submarine cable under the water by easily and accurately detecting the cable position and a method for guiding the same by utilizing the characteristics unique to submarine cables, by supplying an AC only to the portion of the cable between two arbitrary repeaters through a so-called transformer-coupling system to generate an AC magnetic field, and by detecting the magnetic field with a magnetic field detector.

Alternating current induction method using an annular magnetic coupling

The present invention aims at providing a method and a device for guiding the cable burying device along the cable effectively as well as accurately even if the cable should be reburied after repairment. The present invention is mainly characterized in that an ultrasonic command signal transmitted from an ultrasonic transmitter/receiver mounted upon the cable burying device is received by an ultrasonic, transponder which has been mounted on the cable. An ultrasonic signal is transmitted in turn from said ultrasonic transponder to be received by said ultrasonic transmitter/receiver so that the position of said ultrasonic transponder on the cable is detected by processing such signals. The present invention is further characterized in that four ultrasonic wave receiving elements are arranged in a square form and in parallel with a horizontal face in the cable burying device, that an ultrasonic transmitter/receiver element is provided at the center of the square, that a support frame is mounted on the outer periphery of the cable, that a rotating member is provided to be freely rotatable via bearings on the outside of the support frame, that an ultrasonic wave transmitter/receiver element is provided on said rotating member.

Guiding method for cable burying device and a device therefor

The present invention has an object to provide an underwater cable burying device which can accurately be guided to align with the cables in the process of burying even if the cables have to be re-buried. The device according to the present invention is characterized in that a travelling device is provided on the body of the device which is further provided with a trenching device at the middle portion thereof, that a cable clamp member and a cable engaging member are provided at an arm projecting forward from the said device body and that said respective devices are controlled through a control cable on the mother ship.

Growing community of inventors

Hachiohji, Japan

Kenichi Asakawa