Kokusai Denshin Denwa Co., Ltd.

Duo-fast Corporation

Yuichi Shirasaki

Yoshinao Iwamoto

Kenichi Asakawa

Masayuki Fujise

Kazuomi Yamamura

Shizuo Suzuki

Toshio Izawa

Takasuke Fukui

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 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 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

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

A cable buried under a sea bottom is located by causing to flow in the cable an AC current, and measuring the magnetic flux near the cable. The present cable location system comprises (a) a vehicle for mounting a flux detector, (b) means for applying an alternating current in the cable to be detected, to produce magnetic flux around the cable, (c) a three dimensional flux detector having three detector elements, each having cosine sensitivity characteristics, mounted on said vehicle, the maximum sensitivity direction of each element being perpendicular to one another, and the maximum sensitivity direction of one of the detector elements being directed in the vertical direction, (d) means for separating the output signals of each of said detector elements into a DC component which is caused by the earth's magnetic field and an AC component which is caused by said alternating current, (e) means for determining the direction of the cable from the DC and AC output signals of two detector elements which have directivity in the horizontal plane, and (f) means for determining the horizontal distance and the vertical distance between the cable and the cable detecting system from the AC output signals of the detector elements based on the principle that the magnitude of the flux is inversely proportional to the distance to the cable and the direction of the flux is in the tangential direction of a circle having the center on its cable.

System for detecting a cable buried under the seabed

A cable buried under a sea bottom is located by flowing in the cable an electrical current, and measuring the magnetic flux by said current at four points near the cable. The present cable detecting system comprises nondirectional flux measurement means searching for the cable to be detected and measuring the flux by said electric current at four vertex points forming a horizontal square plane, means for transmitting the measured values to a cable ship, means mounted in said ship for providing squared amplitude ratios of each of said magnetic flux to a selected one of the magnetic flux, and means for providing the distance to the cable from the center of said four vertex points, the angle between the transverse direction to the cable and the extension of the diagonal line of said four vertex points, and the depth between the cable and said horizontal square plane, on the principle that said amplitude ratio is equal respectively to the reciprocal of the corresponding ratio of the distance between said cable and each of said points.

Growing community of inventors

Tokyo, Japan

Yuichi Shirasaki