A Review of Recent Development of Efficient High-Power Continuous- Wave Er-Yb Codoped Fiber Amplifiers

In this paper, we will review the recent developments of high-power continuous-wave (CW) Er-Yb codoped fiber amplifiers (EYDFAs). Several related patents and a couple of methods of improving the performance of high-power EYDFAs are reviewed. Current research results show that the Yb-band amplified spontaneous emission (Yb-ASE) is the main reason that limits the efficiency and stability of an EYDFA at high pump power. Several methods and experimental results dedicated to suppress the Yb-ASE are introduced. Current and potential future developments of high-power EYDFAs are summarized in the last part of this paper.