The nonlinear noise effect in optical fibers is an important factor to limit the development of high power fiber lasers. The threshold of nonlinear effect can be improved by suppressing the time domain instability (self-pulsing phenomenon) of lasers. On the basis of an all-fiber resonator cavity, a simple fiber Fabry-Perot cavity is incorporated. The noise dither is reduced to one third of its original value and stable continuous laser output suppressed by self-pulsing is realized. This simple cavity structure can maintain a higher slope efficiency (76.5%) and can implement high power laser output (48.7 W bump light can generate 36.5 W laser). The all fiber resonator cavity in the cavity structure not only can be used as a stable continuous laser, but also can be used as the seed of higher power fiber amplifiers for limiting the generation of nonlinear effect.