Dear all, I had made some modifacation, welcome your comment on the modified one.
Cable ship Visit Report At the beginning of the Sep, a Singapore- based cable vessel -ASEAN Explorer returned to its homeport from the Indian Ocean; while it still stayed in harbor, IEEE Photonics Society Singapore Chapter organized a visit to it, and the visit got the support from SingTel. As there were no more than 50 cable vessels in the world, and most of time such ships were on the sea, so such an opportunity was really valuable.
Using submarine cable for communication has near 150 years history, but it had not been the reigning technique for intercontinental communication until the fiber communication system presented exclusive advantages in late 1980s. Now, over 95% of trans-ocean communication is sent via submarine cable, and the cable ship is dedicated to lay fiber based cable, and it was started form 1988 first commercial trans-oceanic fibre communication system TAT8.
The cable ship was specially designed and used to lay or maintain cables under deep water. Distinguished from other types of ship, it has a large superstructure, and several big cable tanks. It always outfits with the latest navigation and dynamic positioning controlling equipments. Furthermore it also equips with remotely controlled vehicle, seaplow, cable drum, linear cable engine, and vast communication equipments. The cable ship is generally designed for deep water operation, for the shallow water, near terrene construction barge was used in the water depth less than 10m, and diver was employed in the water depth less than 2m.
The cable laying operation begins with the cable being 'floated' ashore to the landing position from the cable ship, and then the floatation bags are removed and the cable settles to the seabed. After that the cable ship follows the pre-determinate route laying the cable as required. Once the ship arrived at the other cable end (previously installed and buoyed off), the ship would adjust its position so that both cable ends could be brought to the board, then the final splice of cable was made. Upon completion of the final splice joint, the cable would be deployed on the seabed.
The maintain operation starts from roughly locating the fault form the terminal stations, then the cable ship with the grapnel, which was a special device that can simultaneously cut and seize cables was dispatched to the nearby regions. Once the cable was found, it would be cut in situ and brought onto the ship by the grapnel. On the ship, a buoy would be attached to the end of the cut cable, and then replaced them on the ocean surface. After that, the ship went to find the other end of the cable. Once the other end was found, the faulty cable section would be instead by the replacement cable. After that the ship returned to the buoy, and the cable attached to the buoy would be spliced to the replacement cable. Finally, after a series of tests, the cable was released onto the sea bed.
Beside the advanced techniques and highly trained staff, a suitable organize scheme was necessary for balancing the cost, time, and quality. The submarine cable communication system project often adapted the Project Management frame to organize the resource, and the project manager was ultimately responsible for ensuring that the objectives of the project were achieved.
The signal on each fiber -pair of TAT8 was transported at 295.6 Mbit/s. Now 1000Gbit/s can be obtained on each fiber-pair (100 wavelengths to be modulated at 10Gbit/s enabling a capacity of more than 1 Terabit/s per fiber-pair). Seldom can a technique improve itself like the speed that fiber communication has improved, and influences of such improvement were on the way that we living rather than the way that we communicate. If you answer the question what is the Engineering as the practical application of science and math to solve problems, the fiber communication could be taken as the example that can demonstrate well what the Engineering is.
Li Ruoming
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