Submarine Fiber Networks Have the World on a String

Tony Frisch

Submerged in the world's oceans are well over a million kilometers of submarine cable -- enough to circle the globe 30 times -- forming a network of arteries that carry huge volumes of traffic between continents. Although satellite communications can provide traffic to many locations, it plays a complementary role to cable technology, which has the volume capacity necessary for the bulk of international communication (speech, fax, data and Internet protocol).

Electro-optic repeaters and fiber optics were introduced in the 1980s, before which coaxial cables were used. The introduction in the 1990s of optical amplifiers that could process multiple wavelengths opened the door to wavelength division multiplexing (WDM) and signaled a capacity explosion. At the same time, deregulation created a much more competitive environment where the demand for capacity has increased faster than ever. Today a single fiber can provide 640 Gb/s -- more than 1000 times the capacity of the last coaxial cables and roughly equivalent to 8 million uncompressed (64 kb/s) speech circuits. Each cable can contain several fibers...