Submarine Cable System Research Articles

Three Dimensional Dynamic Analysis for Laying and Recovery of Optical Submarine Cables

The author has developed two types of cable laying simulation programs based on three dimensional dynamic analysis method in order to analyze dynamic behavior of cables, repeaters and branching unit during laying and recovery.One is a computer simulation program for laying and recovery of submarine cables with repeaters. This program has following two new functions is addition to conventional cable laying simulation.(1) Slack control laying function. The cable pay-out speed is automatically calculated by internal feed back loop so as to make bottom cable slacks be constant. Using this function, the optimum cable pay -out speed history can be obtained by giving the bottom profile and cable ship speed profile.(2) Tension control laying function. The cable pay-out speed is automatically calculated by internal feed back loop so as to make shipboard tension be constant. The speed error of cable ship measured by 'taut wire' is discussed using this program. This error is exactly analyzed using this tension control laying simulation.The other is a computer program for laying and recovery submarine cables with a cable branching unit. The cable branching unit (BU) is newly installed to the optical submarine cable systems. This newly developed program can analyze dynamic behavior of BU and cables around it, and help to study how to lay BU with sufficient cable slacks and recover it safety.The sea trial was carried out in order to measure hydrodynamic constant of the submarine cable and verify this computer simulation method at the depth of 6000m by attaching sensors to the submarine cable at some intervals. According to the sea trial, the normal drag coefficient Cd was measured to 2.5, andd the cable configuration measured by this experiment was in good agreement with the result of the computer simulation.

First field demonstration of optical submarine cable system using LD-pumped Er-doped optical fibre amplifier

This is a report on the first field demonstration of an optical submarine cable system using an in-line Er-doped optical fibre amplifier pumped by a 1.47μm laser diode. The experiment was performed at an ocean depth of 3000 m. With a maximum optical repeater gain of 20 dB, l.2 Gbit/s intensity-modulated optical signals were transmitted stably during and after installation and also during recovery of the system. Furthermore, the effectiveness of an automatic-gain-control (AGC) scheme proposed for optical amplifiers was confirmed in a practical environment.

The 132 kV AC power cables and the optical fiber cable for the submarine intertie Italy-Elba Island

A 132 kV oil-filled submarine cable transmission system to supply power from mainland Italy (Piombino) to Elba island off its east coast and an associated fiber-optic submarine cable for telecommunication purposes are described. The power system comprises four single-core oil-filled cables and accessories, including an oil pumping plant with a cross-over system. Attention is focused on the system characteristics of the intertie, the environmental conditions and site survey, and the design, manufacture, installation and protection of the cable. Special attention is paid to the design and installation of the fiber-optic cable and its connection to an overhead line and to an exchange. >

Design, manufacture and installation of 150 kV submarine cable system for the Java–Madura interconnection

Java now has a totally-integrated 500 kV, 150 kV and 70 kV transmission network, extending for over 1000 km from east to west. Large modern oil and coal-fired power stations, hydropower stations and even a geothermal power station supply this network which enables power to be produced and transmitted cheaply throughout the island. By comparison, the less densely populated islands have to rely on isolated, small, diesel generating plants at each load centre. A power system development study was commissioned by the British Government in 1979 through the Overseas Development Administration (ODA). The study did reveal that there was a potential for load growth and that in the long term, this would best be served by interconnecting the island power systems to the integrated system on Java. The timing of this link would depend on the rate of load growth. As a result of these studies, the 150 kV submarine cable option was selected as being the most economic. Tenders were invited and the contract for the submarine cable was awarded to BICC Supertension Cables Ltd. who manufactured the cables, in consortium with Balfour Kilpatrick Submarine Cable Unit who were responsible for installation and burial. The submarine cable link was officially inaugurated on 24th March 1987 by the Minister of Mines and Energy at a ceremony held in Arosbaya, a small village at the end of the new distribution system 30 km from the cable landing point.

High reliability planar-type GaInAs/InP heterostructure avalanche photodiodes

High-temperature, long-term life tests of GaInAs/InP heterostructure avalanche photodiodes have been carried out to establish criteria for high reliability photodetectors in 1.55μm-wavelength optical submarine cable systems. A failure rate of less than 0.2 FIT at 10°C was predicted for the first time with an activation energy of 0.7 eV.

Deep sea trial of 1.55 µm optical fibre submarine cable system

The first 6000 m deep sea trial of a 1.55 µm optical fibre submarine cable system was successfully conducted in the Pacific Ocean, near Torishima Island, in January 1988. By using 1.55 µm loss-minimised single-mode fibre cables and submerged fully monolithic Si-IC regenerators with DFB lasers, excellent transmission performances at 140, 280 and 565 Mbit/s were obtained through 150 km repeater spacings, respectively.

First sea trial of FSK heterodyne optical transmission system using polarisation diversity

Operation of an FSK heterodyne optical transmission system on the cable ship during the cable-laying, holding, and recovering process in a 6000 m-deep sea trial is demonstrated. It is shown that polarisation diversity is a powerful technique for application to coherent systems in submarine cable systems.

1.55- mu m fiber-optic transmission experiments for long-span submarine cable system design

Results of 1.55- mu m transmission experiments at 140, 280, and 565 Mb/s involving conventional and dispersion-shifted single-mode fibers along the Fabry-Perot laser diode (FP-LD) and distributed-feedback laser diode (DFB-LD) optical sources are discussed. The results show which combination of optical fiber and optical source best meet the requirement of long repeater spacing for each bit rate. The results indicate that to achieve repeater spacing more than 100 km with dispersion-shifted fibers and FP-LD optical sources will impose strict requirements on both the optical fibers and the optical sources even at 280 Mb/s. Alternatively, systems using DFB-LD optical sources will not degrade the transmission performances and will considerably loosen requirements on the fibers and optical sources. A combination of dispersion-shifted fibers and DFB-LD optical sources can further loosen the requirements on the fibers and optical sources in 560-Mb/s systems. >

Submarine optical fibre cable system applications

The transition from analogue coaxial cable to digital optical fibre submarine systems has required a new technology to be established and complementary technologies to be developed for the design, evaluation and operational support of these new systems. The common design parameter throughout is reliability; not only must the overall system design satisfy the reliability objective but the component parts must be shown to exhibit the necessary low level of failure for this to be achieved.1988 sees the commissioning of TAT-8, the first trans atlantic optical fibre submarine cable system. In addition a number of submarine cable systems linking the UK mainland with other British Islands and Europe will be made available. This paper reviews the current generation of submarine cable systems based on 1.3μm and emerging 1.55μm technologies and discusses the opportunities offered to planners and network operators from developments in networking, optical repeaters and non-silica fibres.

The design and realization of a high reliability semiconductor laser for single-mode fiber-optical communication links

Long-haul trunk telecommunication systems, particularly optical submarine cable systems, have especially demanding reliability requirements. The authors describe how the InGaAsP inverted-rib waveguide (IRW) laser was designed for use as the source for such single-mode systems by minimizing known degradation hazards. The results of an extensive reliability assurance program are summarized. This included wafer validation endurance tests, overstress tests, and package design and life tests. The results of 7 million life-test hours confirm that the IRW laser has extremely good reliability performance. >

Communications: ISDN services are introduced worldwide coherent optical communications components are developed in Japan fiber-optic submarine cable systems to span the Pacific additional spectrum space is allocated for mobile communications

The day when voice communications will be sent over the same lines as computer data and images moved closer in 1986 as some U.S. telephone companies held field trials of systems for an integrated-services digital network (ISDN). At the same time, several Japanese companies developed and tested components that promise to make coherent optical communication systems practical. And new spectrum space was opened in the United States for users of mobile communications.

Reliability of the OS-280M Optical Submarine Repeater

The development phase of the OS-280M optical submarine cable system is finished, and currently the mass production lines for the system are arranged so as to satisfy the specific performances and the reliability requirements for the TPC-3 system within its system life of 25 years. KDD developed the reliability assurance system of the repeater components, which began three years ago. In this paper, we will introduce the reliability design of the OS-280M system and will report on the reliability test results obtained until the present time. In conclusion, it will be demonstrated that all of repeater components, i.e., optical semiconductor devices, monolithic IC's, several kinds of optical devices, and conventional components could satisfy the reliability requirements for the OS-280M system.

Cable Section Fault Detection for HVDC Line Protection

For DC line protection of the Hokkaido-Honshu HVDC Link, a submarine cable fault detection system was developed. In this system, a DC line fault is declared when DC currents at both cable heads change mutually in the reverse direction. Combining this detection system with a current difference detection system which operates for any fault occurring on the high voltage DC transmission line, the high voltage DC line protection system is composed. Through the simulator tests and five-year field experience, the detection system has been verified to be satisfactory.

Design and test results of a deep sea optical fiber submarine cable

AbstractLong‐distance submarine cable telecommunication systems using low‐loss optical fiber have been investigated more and more extensively. They are expected for international digital trunk because of their economical feature brought by smaller diameter cable and longer repeater spacing as well as large transmission capacity. This paper describes a design concept for deep sea optical submarine cable and proposes a three‐split metal pipe structure as the pressure‐resistant layer against the high water pressure. This structure features good manufacturability of small diameter and thick‐wall metal pipe, particularly cable of long run length.A prototype anti‐water propagation cable was manufactured using the pipe described above and the mechanical and transmission performance was measured in elevated temperatures, pressures, and tensions in the ocean simulator on the land. Also, test operations of the cable laying, holding and recovery on the 7000‐m deep ocean bed were performed. From the results obtained, we find that the estimated loss change is less than 0.02 dB/km, which makes the proposed optical fiber cable structure feasible for deep sea submarine cable system application.

Cable Section Fault Detection for HVDC Line Protection

For DC line protection of the Hokkaido-Honshu HVDC Link, a submarine cable fault detection system was developed. In this system, a DC line fault is declared when DC currents at both cable heads change mutually in the reverse direction. Combining this detection system with a current difference detection system which operates for any fault occurring on the high voltage DC transmission line, the high voltage DC line protection system is composed. Through the simulator tests and five-year field experience, the detection system has been verified to be satisfactory.

Self-core-alignment arc-fusion splicer based on a simple local monitoring method

We have developed an arc-fusion splicer with a self-core-alignment function based on cladding-mode-leakage light power monitoring that incorporates a microprocessor, piezoelectric elements, and a photoreceiver with high sensitivity, for monitoring the leakage light power without bending the receiving fiber. The design and the performance of the splicer are presented. Using the splicer, we successfully demonstrate the splicings of single-mode fibers in a repeater section of an experimental optical submarine cable transmission system. The required time for one splicing including the self-core-alignment process is only 50 s and we have obtained extremely good results with an average splice loss of 0.035 dB for 100 splices at the far end of a 30-km-long single-mode fiber connected with a repeater.

1.3-μm Laser Reliability Determination for Submarine Cable Systems

To meet the stringent requirements of a submarine cable system, our 1.3-μm laser prequalification program has two objectives — first, to define the testing methodology that will accurately evaluate the potential reliability of the laser; and second, to obtain a preliminary indication of laser reliability on which the system configuration can be designed. Our testing methodology involves a combination of step-temperature, step-power, and isothermal testing over the temperature interval between 10 and 80°C and power levels of 1 to 5 mW per facet. Our results show that the long-term degradation process is thermally accelerated, with a median activation energy of 1 eV and a standard deviation of 0.13 eV. By using these activation energies, in conjunction with our measurements of degradation rates, we can project laser performance to 10°C, i.e., system operating temperature. It is estimated that the median time to failure for “light bulb” operation at 10°C is over 2 × 107 hours; and with 98-percent probability it is greater than 5 × 106 hours. Hence, when viewed strictly in terms of light bulb sources of stimulated power, these 1.3-μm lasers have adequate life. In addition, other potential operational malfunctions are being investigated, and they do not seem to change our basic conclusion about the usefulness of these 1.3-μm lasers for submarine cable application.

Recent advances in submarine optical fiber cable transmission systems in Japan

Submarine optical fiber cable transmission systems are promising successors to existing submarine coaxial cable systems. This paper will review the history and the state of the art of the submarine optical fiber cable transmission technology, and the submarine optical fiber cable transmission systems named FS-400M and OS-280M being developed by NTT and KDD, respectively, in Japan.

A design and experimental results of the OS-280M optical submarine repeater circuits

This paper describes the design philosophy and the experimental results of the optical submarine repeater for the OS-280M optical fiber submarine cable system to be installed across the ocean. This repeater which employs the information rate of 280 Mbit/s, the optical wavelength of 1.3 μ, and is implemented with monolithic ICs, features high reliability, long repeater spans, and the supervisory systems. The test results show that the average optical output power is - 1.4 dBm for the mark density of 1/2, the minimum average power of the optical input for the BER 10 is about -38 dBm at the room temperature, and other specifications are also well satisfied.

Design and Test Results of an Optical Fiber Feedthrough for an Optical Submarine Repeater

A new hermetic sealing structure is described in which optical fibers are metal coated and sealed off. The gap between the fibers and the metal pipe is filled with solder. The sealing structure is used as a feedthrough of a repeater for a long-haul optical fiber submarine cable system. According to theoretical study, airtightness was found reliable for a long period of time by utilizing a self-seal effect operating at the time of pressurizing through the structure where circumferences of fibers are soldered for sealing. Manufacture on trial proved that perfect airtightness was achieved even after a heat cycle test (60°C- -10°C) and shock test (50 G). The incremental loss due to temperature changes in the range from 60°C to - 10°C was less than 0.015 dB and an incremental loss of 0.06 dB or less was observed when the structure was pressurized by 800 kg/cm2, however no residual loss could be found.