Amplitude-flattened frequency combs in the moving photonic crystals

TL;DR

This paper investigates how moving photonic crystal waveguides can generate frequency combs, with defect engineering enhancing sideband amplitudes and spectral properties.

Contribution

It introduces the concept of amplitude-flattened frequency combs in moving PCWs and shows how defect modifications influence spectral characteristics.

Findings

Frequency combs can be generated in moving hollow-core PCWs.

Introduction of periodic defects enhances and equalizes sideband amplitudes.

Spatial mode distribution critically affects comb spectral properties.

Abstract

In this paper, we explore the spectral properties of the moving hollow-core photonic crystal waveguides (PCWs). We find that frequency combs could be generated in the hollow cores of the moving PCWs. Besides, amplitudes of the sidebands in the generated frequency combs are strongly dependent on the spatial field distribution of the core-guided modes of stationary PCWs. Particularly, we find that introduction of the periodic point defects to the innermost rows of the PCW hollow core would significantly modify the spatial field distributions of the guided modes, leading to appearance of the tightly localized defect modes. This, in turn, leads to the enhancement and equalization of the amplitudes of the side bands in the frequency combs generated by the moving PCWs.