Abstract

The increasing demand for traffic expansion, originating from various needs and expanding supply sources, now became an inevitable as well irresistible trend for modern society. Optical communication system, which forms the fundamental physical layer for this global network, cannot be an exception from this mega-trend. Thulium doped fiber amplifiers (TDFA) for S-band applications can be considered one of the key vehicles, which will enable even larger transmission capacity in the future. Even there exist several different pumping approaches^1–5 for the TDFA from its rather complex transition band structures, the underlying physics can be summarized in a simple manner—Overcome the fast lifetime in the signal transition band (³H₄ – ³F₄), to achieve a good inversion for the amplification process. After the recently achieved most intensive research efforts to find the effective pumping configurations, there should also follow equivalent efforts to reveal the inner dynamics for the intelligent system applications. Still, so far, there have not been serious investigations on system related issues for TDFA, from the lack of understandings, and difficulties in constructing appropriate characterization set-up.

© 2002 Optical Society of America