Recent advances in microwave photonics instantaneous frequency measurements

This paper reviews the field of microwave photonics instantaneous frequency measurements (IFM). It aims to consolidate the literature, explains the key implementations and reviews the recent developments. Current photonic IFMs are capable of operating over a wide bandwidth with a good resolution. However, their implementations are often based on discrete components and exhibit limited dynamic range and moderate efficiency. Photonic integration and improvements of dynamic range and efficiency are thus necessary, and they are anticipated as the future research directions and developments.