Synthetic frequency dimensions in dynamically modulated ring resonators

The concept of synthetic dimensions in photonics has attracted rapidly growing interest in the past few years. Among a variety of photonic systems, the ring resonator system under dynamic modulation has been investigated in depth both in theory and experiment and has proven to be a powerful way to build synthetic frequency dimensions. In this Tutorial, we start with a pedagogical introduction to the theoretical approaches in describing the dynamically modulated ring resonator system and then review experimental methods in building such a system. Moreover, we discuss important physical phenomena in synthetic dimensions, including nontrivial topological physics. This Tutorial provides a pathway toward studying the dynamically modulated ring resonator system and understanding synthetic dimensions in photonics and discusses future prospects for both fundamental research and practical applications using synthetic dimensions. (c) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).