Low Loss and Low Dispersion Fiber for Transmission Applications in the Terahertz Regime

In this letter we present a novel slotted core fiber incorporating a slotted cladding for the terahertz band. The modal properties of the designed fiber are numerically investigated based on an efficient finite element method (FEM). Simulation results of the fiber exhibit both a low material absorption loss of 0.0103–0.0145 cm-1 and low dispersion below 0.5 ps/THz/cm within the 0.5–0.9 THz range. Additionally, a number of other features of the fiber have been evaluated

3D printed hollow-core terahertz fibers

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESPA - FUNDAÇÃO AMAZÔNIA DE AMPARO A ESTUDOS E PESQUISASCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORThis paper reviews the subject of 3D printed hollow-core fibers for the propagation of terahertz (THz) waves. Several hollow and microstructured core fibers have been proposed in the literature as candidates for low-loss terahertz guidance. In this review, we focus on 3D printed hollow-core fibers with designs that cannot be easily created by conventional fiber fabrication techniques. We first review the fibers according to their guiding mechanism: photonic bandgap, antiresonant effect, and Bragg effect. We then present the modeling, fabrication, and characterization of a 3D printed Bragg and two antiresonant fibers, highlighting the advantages of using 3D printers as a path to make the fabrication of complex 3D fiber structures fast and cost-effective.63111CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESPA - FUNDAÇÃO AMAZÔNIA DE AMPARO A ESTUDOS E PESQUISASCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESPA - FUNDAÇÃO AMAZÔNIA DE AMPARO A ESTUDOS E PESQUISASCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORSem informaçãoSem informaçãoSem informaçã

Terahertz optical fibers [Invited]

Abstract not available.Md. Saiful Islam, Cristiano M.B. Cordeiro, Marcos A.R. Franco, Jakeya Sultana, Alice L.S. Cruz, and Derek Abbot

Terahertz Sensor via Ultralow-Loss Dispersion-Flattened Polymer Optical Fiber: Design and Analysis

A novel cyclic olefin copolymer (COC)-based polymer optical fiber (POF) with a rectangular porous core is designed for terahertz (THz) sensing by the finite element method. The numerical simulations showed an ultrahigh relative sensitivity of 89.73% of the x-polarization mode at a frequency of 1.2 THz and under optimum design conditions. In addition to this, they showed an ultralow confinement loss of 2.18 × 10−12 cm−1, a high birefringence of 1.91 × 10−3, a numerical aperture of 0.33, and an effective mode area of 1.65 × 105 μm2 was obtained for optimum design conditions. Moreover, the range dispersion variation was within 0.7 ± 0.41 ps/THz/cm, with the frequency range of 1.0–1.4 THz. Compared with the traditional sensor, the late-model sensor will have application value in THz sensing and communication

Design and Analysis of Advanced Photonic Devices for Electromagnetic Transmission and Sensing

In this thesis, we report the investigation of advanced photonic devices for electromagnetic transmission and biochemical sensing in the terahertz and optical regimes. The choice of material for designing a terahertz device is deemed to be one of the most crucial factors. First, we consider materials that are frequently used in making terahertz devices. We experimentally demonstrate the optical, thermal, and chemical properties of various chosen glasses, polymers, and resin to select the optimal material for terahertz. Second, we perform a broad review on terahertz optical fibres—this includes various fibre categories, their guiding mechanisms, fabrication methodologies, possible experimental methodologies, and applications. Third, we analyse and demonstrate the design of various fibre structures for terahertz transmission and sensing, and then perform experiments on a hollow core antiresonant fibre. We demonstrate successful fabrication of an asymmetrical Zeonex fibre using a novel fabrication method. This is carried out by using a tabletop horizontal extruder designed for producing polymer filaments. The fabricated fibre is then experimentally investigated for terahertz transmission and gas sensing. Fourth, we study optical fibre based surface plasmon resonance biosensors for operation in the optical regime. Theoretical studies are undertaken to obtain the best possible sensor in consideration of performance, experimental feasibility, and fabrication. One of the optimized sensors is then fabricated as a possible candidate for possible realworld sensing applications. Finally, we study metasurface planar devices for achieving high sensitivity and quality factor in the terahertz regime. We first demonstrate a tunable graphene metasurface that can achieve multi-band absorption and high refractometric sensing. Later, we demonstrate on an all-dielectric metasurface that reports highest Q-factor in the terahertz regime. We fabricate and experiment on the dielectric metasurface and find good agreement with the simulation.Thesis (Ph.D.) -- University of Adelaide, School of Electrical & Electronic Engineering, 202

Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

Effects of Triangular Core Rotation of a Hybrid Porous Core Terahertz Waveguide

In this paper, we investigate the effects for rotating the triangular core air hole arrangements of a hybrid design porous core fiber. The triangular core has been rotated in anti-clockwise direction to evaluate the impact on different waveguide properties. Effective Material Loss (EML), confinement loss, bending loss, dispersion characteristics and fraction of power flow are calculated to determine the impacts for rotating the triangular core. The porous fiber represented here has a hybrid design in the core area which includes circular rings with central triangular air hole arrangement. The cladding of the investigated fiber has a hexagonal array of air hole distribution. For optimum parameters the reported hybrid porous core fiber shows a flat EML of ±0.000416 cm-1 from 1.5 to 5 terahertz (THz) range and a near zero dispersion of 0.4±0.042 ps/THz/cm from 1.25 to 5.0 THz. Negligible confinement and bending losses are reported for this new type of hybrid porous core design. With improved concept of air hole distribution and exceptional waveguide properties, the reported porous core fiber can be considered as a vital forwarding step in this field of research

Low-Loss Polytetrafluoroethylene Hexagonal Porous Fiber for Terahertz Pulse Transmission in the 6G Mobile Communication Window

Hexagonal porous optical fiber without a central defect is proposed and numerically analyzed with the finite element method (FEM) for transmitting terahertz (THz) electromagnetic wave pulse. In experiments, the transmission characteristics of polytetrafluoroethylene (PTFE) hexagonal porous optical fibers were measured using a THz time-domain spectroscopy (THz-TDS) system. To precisely estimate the effective material loss (EML), we measured the refractive index and absorption coefficient of PTFE in the THz range to use them in FEM analyses, and the EML of the porous fiber was estimated to be lower than that of a bulk rod as large as by a factor of 2 in the frequency range from 0.1 to 0.33 THz. In experiments, we measured the transmission characteristics of both the porous fibers and the bulk rod, to confirm a significant improvement in THz wave transmission nearly by an order of magnitude in the 6G telecommunication window, showing a better performance than theoretical estimations.ope

Photonic crystal fibre: The ultra-flattened dispersion regime

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