Microwave Photonic Filter for Fiber Optic Sensing Applications: A Review

In this work, a detailed analysis of microwave photonic filters (MPFs) is discussed in the context of fiber optic sensing and measurement techniques. At first MPFs are reviewed in terms of classification and characteristics, followed by scope of reconfiguration in a photonic system, applications in aerospace, and associated challenges in implementation. Emerging technologies and advanced systems require featured photonic-assisted detections and processing. In this direction, multi-featured detection schemes like coherent detection, in-phase quadrature detection, Nyquist bandwidth detection and heterodyne detection are discussed. Further for the signal processing and system performance evaluation point of view, time-frequency analysis, phase noise measuring technique, and spurious free dynamic range analysis are given in detail. The discussion is extended for the application in microwave sensing through photonic filters. The key sensing discussion involves compressive sensing, microwave photonic interferometry and interrogation, and sensing of various physical attributes. Photonic filters provide the potential for microwave measurements in aerial systems. The most typical measurements in such systems include real-time frequency evaluation, the demand for a high-resolution and high sensitivity measuring device, Doppler frequency measurement, frequency scanning, and angle of arrivals. Various photonic techniques for such measurements are reviewed, as well as newly developed photonic airborne systems.