The fiber technology provides many advantages for the front end of a laser driver, such as convenience to divide, robustness and stability. A fiber front end scheme is proposed to meet the requirements of next generation high-power petawatt laser facility. Experimental investigation has been done to focus on the broadening and amplification of the chirped pulse. Phase-locked signal of the mode-locked fiber laser is set as the reference clock for the system to synchronize the optical switches. Waveguide amplitude modulator is used to choose the needed frequency of signal. Acoustic optical modulators (AOM) are used to restrain the amplified spontaneous emission (ASE) between fiber amplifiers. Experimental results show that after passing through the large-mode-area ytterbium amplifier, chirped pulse with 4.1-kW peak power, 760-ps is obtained. High degree of robustness, reliability and ease of use make this fiber front end an optional seed pulse for high-power short pulse laser facilities.