Microwave frequency quadrupling based on optical intensity modulation

Photonic generation of microwave signals is a novel and very attractive for application such as radio-over-fiber for wireless communication, broadband wireless access networks, radar and satellite communications. Photonic microwave frequency multiplication based on external intensity modulation has been considered as an effective solution for frequency tunable microwave and millimeter wave signal generation. In this paper, we analyze and demonstrate a technique for photonically assisted microwave frequency quadrupling. A theoretical analysis to achieve the microwave frequency quadrupling using two cascaded Mach-Zehnder modulators is presented. By this technique, a four-fold microwave or millimeter wave signal are photonically generated without the need for an electrical or optical filter. The detailed simulations are presented in electrical and optical domain to investigate the performance of the developed technique. We have demonstrated experimentally the implementation of a microwave frequency quadrupler in the frequency range of 24 GHz to 34 GHz. The generated microwave signal has a very narrow linewidth along with the feature of wideband frequency tunability.