Femtosecond mode-locked lasers are key parts of optical frequency combs which allows a directly link from microwave frequency standards to optical frequencies. In this paper, we report on a 186 MHz mode-locked Erbium-doped fiber femtosecond laser developed for 9.2 GHz ultra-low-noise signal generation. This laser keeps mode-locked states within a large pump power dynamic range (from 300 mW to 1000 mW), and the relative intensity noise of the laser is about −118 dBc/Hz@1 Hz, below −130 dBc/Hz for frequencies higher than 10 Hz.