Antiresonant Layer Research Articles

Low loss negative curvature hollow core fiber in visible red-light and near-infrared bands

Considering the low loss transmission and commercialization of hollow core fiber, negative curvature hollow core fiber (NC-HCF) has become a research hotspot in recent years. We report an innovative NC-HCF with an antiresonant layer inside the cladding tubes based on semi-ellipse and semi-circle structures. Based on the COMSOL simulation, it exhibits an ultralow loss from 0.6 to 1.6μm transmission band. On the one hand, as for semi-ellipse and semi-circle with antiresonant layer structure, the fiber lowest confinement loss (CL) of LP01 mode reaches a lowest value of 7.608 × 10 − 4 dB / km at 0.78 μm, and the high-order mode suppression ratio (HOMER) value can reach 4069. On the other hand, the semi-circle and semi-ellipse with antiresonant layer fiber structure shows the lowest CL of 1.675 × 10 − 4 dB / km at 0.79 μm, and the value of HOMER is 1776. Moreover, based on the fabrication tolerance analysis, the hollow core fibers proposed indicate better performance.

Prospects and limitations of bottom-up fabricated hollow-core waveguides

We perform a numerical simulation study of hollow-core anti-resonant reflection optical waveguides (ARROWs) fabricated using lithography and material deposition in the context of their suitability as a platform for on-chip photonic quantum information processing. We explore the effects of the core size, the number of pairs of anti-resonant layers surrounding the hollow core, and the refractive index contrast between the anti-resonant layer materials on propagation losses in the waveguide. Additionally, we investigate the feasibility of integrating these waveguides with Bragg gratings and dielectric metasurfaces to form on-chip cavities that could act as nonlinear optical elements controllable with single photons when loaded with atomic ensembles.

Liquid Core ARROW Waveguides by Atomic Layer Deposition

We report on the use of the atomic layer deposition (ALD) process for fabricating liquid core antiresonant reflecting optical waveguides (ARROWs). The ALD permits the deposition of a very conformal sub-100-nm titanium dioxide antiresonant layer. This results in a low loss liquid core ARROW waveguide with a broadband output transmission spectrum. Optical transmitted spectrum from the fabricated structure has been reported, and the measured attenuation losses agree with the theoretical predictions.

A-SiC:H anti-resonant layer ARROW waveguides

Over the last decades, anti-resonant reflecting optical waveguides (ARROW) have been used in different integrated optics applications. In this type of waveguide, light confinement is partially achieved through an anti-resonant reflection. In this work, the simulation, fabrication and characterization of ARROW waveguides using dielectric films deposited by a plasma-enhanced chemical vapor deposition (PECVD) technique, at low temperatures ( ∼ 300 °C), are presented. Silicon oxynitride (SiO x N y ) films were used as core and second cladding layers and amorphous hydrogenated silicon carbide (a-SiC:H) films as first cladding layer. Furthermore, numerical simulations were performed using homemade routines based on two computational methods: the transfer matrix method (TMM) for the determination of the optimum thickness of the Fabry-Perot layers; and the non-uniform finite difference method (NU-FDM) for 2D design and determination of the maximum width that yields single-mode operation. The utilization of a silicon carbide anti-resonant layer resulted in low optical attenuations, which is due to the high refractive index difference between the core and this layer. Finally, for comparison purposes, optical waveguides using titanium oxide (TiO 2 ) as the first ARROW layer were also fabricated and characterized.

Tio2 Anti-Resonant Layer Arrow Waveguides

The simulation, fabrication and characterization of ARROW waveguides using dielectric films deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and Sputtering techniques, are presented in this work. Amorphous titanium oxide (TiO2) films were used as first cladding layer and silicon oxynitride (SiOxNy) films, as core and second cladding layers. Furthermore, homemade routines based in two computational methods were developed, for numerical simulations: Transfer Matrix Method (TMM) for the determination of the optimum thickness values of the Fabry-Perot layers, and the Finite Difference Method (FDM) for 2D design and determination of the maximum width that allows single-mode operation. The utilization of titanium oxide as first anti-resonant layer resulted in low optical attenuations, since high interlayer refractive index differences can be obtained.

Colors of thin films, antiresonant phenomena in optical systems, and the limiting loss of modes in hollow optical waveguides

Wave-theory arguments often used to explain colors of thin films are applied to derive simple, physically instructive relations providing a quantitative understanding of transmission spectra of hollow optical waveguides with a complex structure of the cladding. Antiresonant phenomena in complicatedoptical waveguide systems are shown to weaken the coupling between certain groups of waveguide modes, suggesting ways to substantially reduce optical loss and radically improve the beam quality of radiation transmitted through hollow waveguides. It has been revealed that the presence of a single Fabry–Perot type antiresonant layer in a waveguide cladding considerably lowers the waveguide loss and enhances the suppression of high-order waveguide modes relative to standard, capillary waveguides with a solid cladding. Transmission of optical signals over large distances, however, requires waveguides with a periodically structured antiresonant cladding. The loss in suchwaveguides exponentially decreases, while the efficiency of high-order mode suppression exponentially increases with the growth in the number of structure periods in the waveguidecladding.