We present the full-optical realization of spectrum analyzer system based on electromagnetic induced transparency (EIT) and Fabry-Perot interferometer. In this system, the index of refraction variation due to variation of the coupling field intensity in the EIT process can be used for detection of the incident light components in the frequency domain. For extracting the frequency component, the transmission coefficient of the Fabry-Perot interferometer is used. Our proposed system can monitor the incident spectrum content at least for 5-THz bandwidth.