Microwave Photonic Links and Transversal Microwave Photonic Applications

With the help of photonic techniques, microwave photonic links (MPLs) have remarkable advantages in terms of generating, transmitting, and processing analog or microwave signals with high frequency or wide bandwidth relative to traditional electrical systems, which have been widely and deeply researched over the past few decades. Recently, significant advances in photonic integrated technologies have stimulated and promoted the emergence of high-performance integrated components that make up MPLs, thereby greatly enriching their capabilities and further expanding their application prospects. Here, we review the recent advances in MPLs, which involve high-performance MPLs, MPLs for microwave photonic radar systems, MPLs for optical signal processing, and MPLs for optical neuromorphic computing. Firstly, key parameters of MPLs performance are analyzed, and the approaches to constructing high-performance (i.e., broadband and large dynamic range) MPLs are summarized. Secondly, the architecture of MPLs used for different function modules of microwave photonic radar systems is reviewed, wherein the recent schemes based on MPLs are classified according to radar signal generation, radar signal processing, and radar signal transmission. Thirdly, the existing system schemes of MPLs for implementing optical signal processing are outlined, which include microwave photonic filters, integrators, channelizers, and phased array antennas. Fourthly, the photonic neuromorphic computing systems, a nascent flourished applications field engendered by integrated or partially integrated MPLs, are introduced and reviewed, which provide readers with a novel understanding of MPL and its potential applications. Finally, we briefly present our outlook on key technologies needed to further advance MPL techniques and their relative applications.