A simple clock enhanced loop of cascaded electro-absorption modulators(EAMs)and 10GHz clock recovery modules is presented.The intensity of harmonic of clock-frequency component is analyzed theoretically and verified experimentally in a 160Gb/s OTDM 100km transmission system.The 10GHz clock component is enhanced obviously before launching into the clock recovery module and the recovered clock signal exhibits low rms jitter of < 400 fs.Moreover,completely error-free(10-12)transmission is observed for more than two hours without using forward error correction technology.The power penalty is about 3.6dB.The proposed loop has merits of enhancing base clock component,simultaneously de-multiplexing and clock recovery,which make the performance of this loop more stable and high suppression of non-target channels.