Provided are a frequency extracting apparatus and a signal extracting system employing the same. The signal extracting system can reduce the effect of an input signal pattern by extracting two frequency components and beating them to extract a desired clock signal, and improve a signal-to-noise ratio of an extracted clock signal. The frequency extracting apparatus includes: a circulator for changing an output direction of an input signal; a reflective filter for extracting a desired frequency component among frequency components of the input signal; a wavelength and amplitude controlling unit; and the frequency amplitude controller.