Optical amplifiers for submarine cable systems

In the coaxial era 1950-86 submarine system manufacturers were developing a new repeater design on average once every 7 years. Since the advent of optical fibres, this pace now appears leisurely. Market share is largely determined by the number of circuits/fibre and technological improvements are constantly evolving to increase this. Bit rates have rapidly moved from the initial 280 Mbit/s per fibre pair to the current position where orders have been placed for rates up to 1.6 Gbit/s. Furthermore, there seems to be no slowing down of the market demand. The challenge for the manufacturer in this new and fiercely competitive world is to maintain the quality levels that submarine applications demand, whilst introducing new components and techniques to cope with the ever higher bit rates. It is against this background that the possible introduction of optical amplifiers needs to be placed. This paper assesses the prospects for amplifier based systems, what they may look like, and what their limitations are likely to be