Modulators for Terahertz Communication: The Current State of the Art.

Z T Ma,J Liu,H D Chen,Z Y Fan,Z X Geng

doi:10.34133/2019/6482975

Abstract

With the increase of communication frequency, terahertz (THz) communication technology has been an important research field; particularly the terahertz modulator is becoming one of the core devices in THz communication system. The modulation performance of a THz communication system depends on the characterization of THz modulator. THz modulators based on different principles and materials have been studied and developed. However, they are still on the way to practical application due to low modulation speed, narrow bandwidth, and insufficient modulation depth. Therefore, we review the research progress of THz modulator in recent years and evaluate devices critically and comprehensively. We focus on the working principles such as electric, optical, optoelectrical, thermal, magnetic, programmable metamaterials and nonlinear modulation methods for THz wave with semiconductors, metamaterials, and 2D materials (such as graphene, molybdenum disulfide, and tungsten disulfide). Furthermore, we propose a guiding rule to select appropriate materials and modulation methods for specific applications in THz communication.

Highlights

The terahertz (THz) wave is firstly used to describe the spectral line frequency coverage of Michelson interferometer by Fleming in 1974 [1]
THz wave occupies a crucial frequency range, because it usually carries vital physical information [7] which can be used in cutting-edge technologies [8, 9] such as wireless high-speed communications [10, 11], biomedical diagnostics [12,13,14], security imaging [15, 16], signal detection [17], and product quality control [18, 19]
Longqing Cong et al demonstrated an active hybrid metasurface integrated with patterned semiconductor inclusions for all-optical active control of terahertz waves [51]

Summary

Introduction

The terahertz (THz) wave is firstly used to describe the spectral line frequency coverage of Michelson interferometer by Fleming in 1974 [1]. THz wave occupies a crucial frequency range, because it usually carries vital physical information [7] which can be used in cutting-edge technologies [8, 9] such as wireless high-speed communications [10, 11], biomedical diagnostics [12,13,14], security imaging [15, 16], signal detection [17], and product quality control [18, 19]. In THz communication system, modulators play a key role It has become a “hot” research field. More and more materials have been used to develop THz modulation devices currently, such as photonic crystals, metamaterial structures, phase change materials, high electron mobility transistors (HEMTs) structures, and graphene. The future development direction and application of THz modulator was proposed

THz Modulation Technique

THz wave

Ferrofluids Metamaterial

Conclusions and Outlook

Findings

Conflicts of Interest