Yb3+ doped double clad fiber laser with all fiber cavity

A novel all fiber cavity Yb^(3+)-doped double-clad fiber laser (DCFL) based on two double-clad fiber (DCF) Bragg grating is presented. The fiber Bragg gratings (FBGs) as the input and output mirrors have been formed in Yb^(3+)-doped DCF with the phase-mask method, and their reflectivities are 99% an