Abstract

In the past year, many attempts have been made to improve the characteristics of praseodymium-doped fiber amplifiers (PDFA) and to apply them to practical systems. The goals of those experiments were to obtain a longer lifetime with lower phonon energy material^1,2 to achieve a higher gain PDFA module with a lower loss host fiber,³ to realize higher output power with higher pump power, and to clarify the amplification characteristics for transmission applications such as CATV and long- haul transmission.^5,6,7 On the basis of our investigations, we summarize recent progress in the improvement of the PDFA characteristics and in the application of the PDFA to practical systems, and also discuss the future prospects for PDFA.

© 1994 Optical Society of America