An optical pipe dream

In the early days of telegraphy, long-haul cables such as the Transatlantic Cable did not incorporate any active devices and were therefore in essence transparent. They represented a pipe over which transmission engineers could send any signals that were viable. Technological progress caused a movement away from this transparency, ultimately ending in today´s regenerated optical systems and whilst there have been enormous advantages to be gained from the movement away from transparency, the emergence of practical optical amplifiers is likely to take us back once again to transparency and the dream of an optical pipe. Before giving further consideration to the benefits of optical pipes it is worth reviewing the basic objectives for the development of future systems. This paper concentrates particularly on undersea applications