ABSTRACT
This work presents the design and multiphysics simulation of a cylindrical waveguide-based optical switch using germanium-antimony-tellurium (GST) as an active phase change material. The innovative cylindrical architecture is theoretically analyzed and evaluated at 1550 nm wavelength for telecommunication applications. The dispersion relation is derived analytically for the first time to model the optical switch, while finite element method (FEM) and finite difference time domain (FDTD) techniques are utilized to simulate the optical modes, light propagation, and phase change dynamics. The fundamental TE01 and HE11 modes are studied in detail, enabling switching between low-loss amorphous and high-loss crystalline GST phases. Increasing the GST thickness is found to increase absorption loss in the crystalline state but also slows down phase transition kinetics, reducing switching speeds. A 10 nm GST layer results in competitive performance metrics of 0.79 dB insertion loss, 13.47 dB extinction ratio, 30 nJ average power consumption, and 3.5 Mb/s bit rate. The combined optical, thermal, and electrical simulation provides comprehensive insights towards developing integrated non-volatile photonic switches and modulators utilizing phase change materials.
ABSTRACT
The objective of this study is the experimental investigation of the silver in diamond-like carbon (Ag/DLC) nanocomposite prepared by the co-deposition of radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) and RF-sputtering. Atomic force microscopy (AFM), X-ray diffraction analyses, ultraviolet-visible (UV-visible) spectroscopy measurements were applied to describe the three-dimensional surface texture data in connection with the statistical, and multifractal analyses. Additional information about structure-property relationships in prepared Ag/DLC nanocomposite was studied in detail to allow a better understanding of the surface micromorphology. The performed analysis revealed the studied samples have multifractal properties and can be included in novel algorithms for graphical representation of complex geometrical shapes and implemented in computer simulation algorithms.
ABSTRACT
INTRODUCTION: In this study, a stereometric analysis of the three dimensional (3-D) surfaces of the Ag/DLC nanocomposite synthesized by RF-PECVD was performed. MATERIALS AND METHODS: Atomic force microscopy in noncontact mode was used to study surface morphology in correlation with multi-parametric statistical analysis. The associated parameters of segmented motifs in conformity with ISO 25178-2:, 2012 have been extracted using MountainsMap® Premium software. The mathematical algorithm computes detached watersheds of hill or dale motifs and determines the maximum and minimum points of motifs. RESULTS AND DISCUSSION: The stereometric analyses with MountainsMap® Premium software provided detailed information on the 3-D surface topography of samples. Fractal analyses revealed the fractal nature of the performed samples is in correlation with the deposition time of samples. Detailed information of manufactured Ag/diamond-like carbon (DLC) nanocomposite is given based on the information about the surface structure, properties, and performance characteristics. The performed analysis allows the high-resolution modeling of Ag/DLC nanocomposite surface microtexture with motif analysis (intrinsic characteristics disclosure and characterization of surfaces fractal), in order to be included in computer interactive simulation algorithms. CONCLUSION: It was found the fractal dimension decreases with the increase of the deposition times on samples.
