At the first time, tunable (up to 40 nm) single frequency ( FWHM <30 kHz) Yb, and Yb/Er doped fiber lasers based on the MOPFA configuration with the output power from 1 W to 10 W in CW have been demonstrated and realized as final products. In particular, the different kind of master oscillators schematics including DBR fiber lasers, ring resonator fiber laser and fiber coupled external cavity LD's have been used. The ultimate output power limitation due to SBS were investigated.