Wide Bandwidth High Capacity Systems

In recent years, the capacity of terrestrial and undersea lightwave communication systems has increased substantially to meet the demand created by the Internet. The capacity of currently deployed wavelength division multiplexed (WDM) systems (40-80 Gb/s), is limited by the number of optical channels. The number of WDM channels (8 or 16) is restricted by the bandwidth (12 nm) of field installed Erbium-doped silica fiber amplifiers (EDFAs). Considerable progress has been made in the improvement of the optical amplifiers and now transmission systems with EDFAs having 35 nm bandwidth are being included in the next generation systems to be deployed soon. Using EDFAs with larger bandwidth, laboratory demonstration of WDM transmission with 32 and 64 channels on both terrestrial and undersea distances has recently been reported. Commercial systems, which employ wider bandwidth EDFAs to obtain 100s of Gb/s total capacity, are scheduled for availability in 1999.