Abstract: Starting with the optical current expression of an electromagnetic wave signal generated by opticalheterodyning,the conditions of optical heterodyning are discussed, and the top frequency and restriction factors for the electromagnetic wave are analyzed. The Matlab simulations show that the top frequency of the electromagnetic wave is mainly restricted by the frequency bandwidth of the photodetector, and is able to cover the top of the radio frequency band. The mm-wave of a ROF system and THz-wave are successfully obtained in optical heterodyning experiment.

Key words: electromagnetic wave, optical heterodyning, top frequency, radio over fiber technology