A novel simple RF-to-digital photonic link based on a single phase modulator

A novel approach to implementing high-linearity microwave photonic link (MPL) based on coherent detection is proposed and experimentally demonstrated. The simultaneous optical in-phase and quadrature (I/Q) signals are implemented using a single phase modulator (PM) in conjunction with a polarization beam splitter (PBS). Thanks to the anisotropic electrooptic coefficient of lithium niobate, the homodyne interferometer link can be implemented with a single PM. The use of a single PM allows the link avoids the matching requirements of dual modulator schemes. The linearization leads to suppression of the third order intermodulation (IMD3) by more than 30-dB compared to the quadrature signal.