Coherent terahertz-to-microwave link using electro-optic-modulated Turing rolls

TL;DR

This paper demonstrates a method to generate low-noise microwave signals from terahertz-frequency Turing rolls in optical microresonators using electro-optic modulation, enabling high spectral purity and stable terahertz-to-microwave links.

Contribution

It introduces electro-optic frequency division with microcombs to synthesize stable microwave signals from terahertz Turing rolls, and actively stabilizes terahertz oscillations for improved frequency stability.

Findings

Fractional frequency instabilities improved by up to six orders of magnitude.

Successful implementation of electro-optic frequency division using microcombs.

Potential for bidirectional terahertz-to-microwave communication links.

Abstract

Arising from modulation instability, Turing rolls in optical Kerr microresonators have been used in the generation of optical frequency combs and the synthesis of microwave and terahertz frequencies. In this work, by applying electro-optic modulation on terahertz-frequency Turing rolls, we implement electro-optic frequency division with a microcomb to synthesize variable low-noise microwave signals. We also actively stabilize the terahertz oscillations to a microwave reference via intracavity power modulation, obtaining fractional frequency instabilities that are better than those of the free-running situation by up to six orders of magnitude. This study not only highlights the extraordinary spectral purity of Turing roll oscillations but also opens the way for bidirectional terahertz-to-microwave links with hybrid optical frequency comb techniques.