CONVERSION EFFICIENCY OF EAM OPTOELECTRONIC FREQUENCY

We analyze the conversion efficiency of an optoelectronic frequency down-converter based on an electroabsorption (EAM) modulator for radio-on-fiber (RoF) uplink applications. The EAM modulator performs the frequency down-conversion of uplink RF signals into optical intermediate frequency (IF) using remotely-fed optical local oscillator (LO) signals. The frequency down-conversion efficiency depends on not only EAM nonlinearity but also optical IF signal powers delivered to the central station. In this paper, we define internal conversion efficiency as the photodetector output power ratio of frequency down-converted signals to EAM-modulating RF signals. Using this definition, we investigate conversion efficiency as functions of EAM bias, optical LO signal power, and optical IF signal power and wavelength, all of which are important design parameters in RoF systems