High-resolution and Fully-programmable Microwave-shaper

TL;DR

This paper presents a novel programmable microwave spectrum processor with high resolution by mapping a sliced optical spectrum processor to the microwave domain, enabling reconfigurable and high-precision microwave spectrum shaping.

Contribution

It introduces a bandwidth-minified optical-to-microwave mapping technique using a high-Q optical resonator and multi-heterodyne, achieving high resolution and reconfigurability beyond traditional methods.

Findings

Achieved microwave spectrum resolution up to tens of MHz.

Demonstrated full reconfigurability of the spectrum processor.

Enhanced group delay variation through optical-to-microwave mapping.

Abstract

We here propose and demonstrate a point-by-point programmable broadband microwave spectrum processor with high-resolution up to tens of MHz. We achieve this by bandwidth-minified mapping a programmable optical spectrum processor, which has much larger bandwidth and lower frequency resolution, to a microwave one, and make sure the mapping is a similarity transformation. As a comparison, the traditional optical-to-microwave mapping based on super-heterodyne is bandwidth-preserved and identical. Here the optical spectrum processor is firstly sliced by a high-quality-factor optical resonator, which has periodic transmission peak with MHz-level bandwidth, and then is mapped to microwave domain by optical-frequency-comb-assisted multi-heterodyne. We demonstrate the high frequency resolution and full function reconfigurability experimentally. In a numerical example, we show that the group delay variation of optical spectrum processor could be greatly enlarged after mapping. The resolution improvement and group delay magnification distinguish our proposal significantly from previous spectrum mapping from optics to microwave.