Abstract

The past 12 months have been an exciting time for undersea lightwave transmission systems research and development. The first transmission systems based on erbium-doped fiber-amplifiers (EDFAs) have been deployed in both the Atlantic and Pacific oceans. In September of 19% the final, segment of the Trans-Atlantic Telephone network TAT-12/13 was placed into service by a consortium of 44 carriers. The TAT-12/13 cables form a ring network in the North Atlantic with two transatlantic cables of 3900 km and 6300 km, and two interconnection cables, each a few hundred kilometers in length. The cable contains two fiber pairs, each carrying a single NRZ (non-retum-to-zero) channel , operating at 5 Gb/s at a wavelength of about 1558 nm. Each cable can carry about 120,000 64 Kb/s circuits, or the equivalent of 600,000 simultaneous phone conversations. In the unlikely event of a cable failure, the ring architecture allows for mutual restoration capability with the use of network protection elements at each of the four landing sights. A similar ring network (Transpacific Cable-5) is nearly ready to go into service in the Pacific. The single-channel 5 Gb/s NRZ technology is also being deployed in the FLAG system (Fiber Link Around the Globe). FLAG will connect 12 countries starting at the European end of TAT-12/13 and proceeding around the globe to the Asian end of TPC-5, via 27,000 km of cable.

© 1996 Optical Society of America