REMOTE AMPLIFICATION IN REPEATERLESS TRANSMISSION-SYSTEMS

Design and implementation of remotely pumped amplifiers in repeaterles s transmission systems are being reviewed. Here, we discuss Raman ampl ifiers, as well as remote pumping of erbium-doped fiber post-and pream plifiers. Since the advent of semiconductor laser-pumped high-power so urces Raman amplification has become a viable alternative to remote er bium-doped fiber amplifiers. The main advantages include simplicity an d low cast of implementation as well as potential retrofitting into al ready installed systems. However, the optimum performance is obtained from a combination of Raman gain and remote erbium-doped fiber amplifi ers. A remote preamplifier experiment including Raman amplification ha s, for example, demonstrated a power budget improvement of 19.7 dB. Ra man amplification by itself offers approximately 7 dB of improvement. (C) 1997 Academic Press.