Designing and analyzing microwave photonic spectral domain filters based on transversal filtering with optical microcombs

TL;DR

This paper provides a comprehensive analysis of microwave photonic spectral filters using microcomb-based transversal filtering, focusing on theoretical limits, experimental distortions, and input bandwidth effects to guide future design and optimization.

Contribution

It offers a detailed performance analysis of microcomb-based microwave photonic filters, including theoretical, experimental, and input bandwidth considerations, which is novel in the field.

Findings

Finite tap numbers limit spectral response accuracy.

Experimental errors cause spectral distortions.

Input bandwidth affects filtering performance.

Abstract

Microwave transversal filters, which are implemented based on the transversal filter structure in digital signal processing, offer a high reconfigurability for achieving a variety of signal processing functions without changing hardware. When implemented using microwave photonic (MWP) technologies, also known as MWP transversal filters, they provide competitive advantages over their electrical counterparts, such as low loss, large operation bandwidth, and strong immunity to electromagnetic interference. Recent advances in high performance optical microcombs provide compact and powerful multiwavelength sources for MWP transversal filters that require a larger number of wavelength channels to achieve high performance, allowing for the demonstration of a diverse range of filter functions with improved performance and new features. Here, we present a comprehensive performance analysis for microcomb based MWP spectral filters based on the transversal filter approach. First, we investigate the theoretical limitations in the filter spectral response induced by finite tap numbers. Next, we analyze the distortions in the filter spectral response resulting from experimental error sources. Finally, we assess the influence of input signals bandwidth on the filtering errors. These results provide a valuable guide for the design and optimization of microcomb-based MWP transversal filters for a variety of applications.