Research on highly Yb3+-doped passive mode-locked fiber ring laser

Theoretical and experimental results on the self-starting passive mode-locked Yb fiber-ring laser generating short pulse are reported. The relations between the laser-cavity parameters and mode-locked pulse characteristics are discussed. 980-nm LD-pumped laser is used as Me pump source and high-concentration Yb3+-doped fiber is adopted as the gain medium. Using the nonlinear polarization rotation (NPR) effect of the fiber, a self-starting stable mode- locked pulse is obtained, with a center wavelength of 1046 mn, a.3-dB bandwidth of 6.01 nm, and a 20-dB bandwidth of 16 mn. The mode-locked threshold power is 150 mW and output power is 26 mW with a 20-MHz repetition rate. (c) 2005 Wiley Periodicals. Inc.