Design and deployment of optically amplified undersea systems

Applying optical amplifier technology to undersea cable systems using repeaters has occurred in a remarkably short time. Exploratory development of this technology at AT&T-Submarine Systems, Inc. (AT&T-SSI) began in 1989, and the first two commercial systems were installed in the Caribbean Sea early in 1994. Among the steps taken to support this aggressive development and deployment schedule were construction and performance evaluation of optical system “testbeds.” Each testbed consists of an optical transmitter and receiver connected by thousands of kilometers of glass fiber and optical amplifiers configured as they would be in an installed system. This paper reports on the results of testbed measurements, and how they affected network system design. It also describes performance measures made during installation and commissioning of the first Caribbean system, to confirm design expectations, and what was learned, from special “first-system” testing, about the limits of this technology.