Power Distribution of Phase-Modulated Microwave Signals in a Dispersive Fiber-Optic Link

An optical phase-modulated signal can be converted to an intensity-modulated signal in a dispersive optical fiber. Due to the intrinsic nonlinearity of optical phase modulation, higher order harmonics will be generated. In this letter, an analytical model to describe the transmission of a phase-modulated microwave signal in a dispersive radio-over-fiber (RoF) link is presented. A compact and closed-form expression of the generated harmonics at the output of the RoF link is derived. Base on the analytical model, results on the power distributions of different orders of harmonics along the RoF link as well as the upper limit of the dynamic range of the RoF system are obtained. The presented model helps simplify the design and analysis of a phase-modulation-based microwave photonic link or system.