Compact Yb-doped fiber laser (YDFL) based on tunable fiber Bragg grating (FBG) with similar to 6 W output power and similar to 45 nm tuning range around 1080 nm has been developed and studied. The laser output power and its spectral width (similar to 0.15 nm) do not change significantly at the tuning, while the FBG reflection coefficient is slightly increasing with an increase in FBG compression. it has been shown that such increase is reasoned by stress-induced changes in FBG's refractive-index modulation amplitude.