Frequency-modulated microwave photonic links for high dynamic-range antenna remoting systems

To support the need to distribute analog signals from microwave antennas dispersed throughout military aircraft, much research has been devoted to developing microwave photonic links (MPLs) with very high linearity and low noise figures. Frequency-modulated (FM) photonic links are a promising technology to provide high dynamic-range signal transmission for these airborne antenna remoting systems. FM lasers, where a phase modulator in the optical cavity varies the optical frequency with applied RF power, have been demonstrated with very high modulation efficiency. Demodulation performed using an optical filter based frequency discriminator and direct detection (FM-DD) (also called slope or interferometric detection) can be engineered for low nonlinearities by optimizing the transfer function of the filter. The combination of a high efficiency FM laser with a discriminator filter for low-distortion demodulation leads to a MPL with signal gain, low noise figure and large dynamic range.