Electro-optical radiofrequency up-converter based on a Semiconductor Optical Amplifier

We demonstrate in this paper the frequency up-conversion of a radiofrequency signal based on a Semiconductor Optical Amplifier (SOA) which can be used for millimeter-wave applications. The SOA gain is electrically modulated by an IF subcarrier carrying data while an optical bi-mode Local Oscillator (LO) separated by a frequency f_LO is injected into the active zone of the SOA. The up-conversion at f_LO is obtained after detection by a photodiode. The characterization of the up-conversion efficiency is done for f_LO = 16 GHz depending on the IF power, the LO power, the bias current of the SOA and the frequency of the IF subcarrier. We show that an EVM (Error Vector Magnitude) less than 6% can be obtained for the frequency up-conversion of a QPSK-modulated IF subcarrier at 1 GHz with a symbol rate of 1.5 MSymb/s.