scholarly journals Subwavelength Grating Structures in Silicon-on-Insulator Waveguides

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
J. H. Schmid ◽  
P. Cheben ◽  
S. Janz ◽  
J. Lapointe ◽  
E. Post ◽  
...  
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Silicon On Insulator ◽  
Experimental Results ◽  
Subwavelength Grating ◽  
Subwavelength Gratings ◽  
Facet Reflectivity ◽  
Difference Time ◽  
Photonic Wire

First implementations of subwavelength gratings (SWGs) in silicon-on-insulator (SOI) waveguides are discussed and demonstrated by experiment and simulations. The subwavelength effect is exploited for making antireflective and highly reflective waveguide facets as well as efficient fiber-chip coupling structures. We demonstrate experimentally that by etching triangular SWGs into SOI waveguide facets, the facet power reflectivity can be reduced from 31% to <2.5%. Similar structures using square gratings can also be used to achieve high facet reflectivity. Finite difference time-domain simulations show that >94% facet reflectivity can be achieved with square SWGs for 5 μm thick SOI waveguides. Finally, SWG fiber-chip couplers for SOI photonic wire waveguides are introduced, including design, simulation, and first experimental results.

scholarly journals Butterfly-Inspired 2D Periodic Tapered-Staggered Subwavelength Gratings Designed Based on Finite Difference Time Domain Method

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Houxiao Wang ◽  
Wei Zhou ◽  
Er Ping Li ◽  
Rakesh Ganpat Mote
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Fdtd Method ◽  
Subwavelength Structures ◽  
Surface Reflection ◽  
Subwavelength Gratings ◽  
Difference Time

The butterfly-inspired 2D periodic tapered-staggered subwavelength gratings were developed mainly using finite difference time domain (FDTD) method, assisted by using focused ion beam (FIB) nanoscale machining or fabrication. The periodic subwavelength structures along the ridges of the designed gratings may change the electric field intensity distribution and weaken the surface reflection. The performance of the designed SiO2gratings is similar to that of the corresponding Si gratings (the predicted reflectance can be less than around 5% for the bandwidth ranging from 0.15 μm to 1 μm). Further, the antireflection performance of the designedx-unspaced gratings is better than that of the correspondingx-spaced gratings. Based on the FDTD designs and simulated results, the butterfly-inspired grating structure was fabricated on the silicon wafer using FIB milling, reporting the possibility to fabricate these FDTD-designed subwavelength grating structures.

scholarly journals Enhanced Sensitivity of Microring Resonator-Based Sensors Using the Finite Difference Time Domain Method to Detect Glucose Levels for Diabetes Monitoring

2020 ◽  
Vol 10 (12) ◽  
pp. 4191
Author(s):  
Lilik Hasanah ◽  
Harbi Setyo Nugroho ◽  
Chandra Wulandari ◽  
Budi Mulyanti ◽  
Dilla Duryha Berhanuddin ◽  
...  
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Microring Resonator ◽  
Silicon On Insulator ◽  
Laser Source ◽  
Quality Factors ◽  
Simulation Design ◽  
Glucose Levels ◽  
Difference Time

The properties of light and its interaction with biological analytes have made it possible to design sophisticated and reliable optical-based biomedical sensors. In this paper, we report the simulation, design, and fabrication of microring resonator (MRR)-based sensors for the detection of diabetic glucose levels. Electron Beam Lithography (EBL) with 1:1 hydrogen silsesquioxane (HSQ) negative tone resist were used to fabricate MRR on a Silicon-on-Insulator (SOI) platform. Scanning Electron Microscopy (SEM) was then used to characterize the morphology of the MRR device. The full-width at half-maximum (FWHM) and quality factors of MRR were obtained by using a tunable laser source (TLS) and optical spectrum analyzer (OSA). In this paper, the three-dimensional Finite Difference Time Domain (3D FDTD) approach has been used to simulate the proposed design. The simulation results show an accurate approximation with the experimental results. Next, the sensitivity of MRR-based sensors to detect glucose levels is obtained. The sensitivity value for glucose level detection in the range 0% to 18% is 69.44 nm/RIU. This proved that our MRR design has a great potential as a sensor to detect diabetic glucose levels.

Investigation of Adhesion Materials for Gold Line-and-Space Surface Plasmon Antenna on SOI-MOS Photodiode

2011 ◽  
Vol 222 ◽  
pp. 201-204 ◽  
Author(s):  
Hiroaki Satoh ◽  
Yuki Matsuo ◽  
Hiroshi Inokawa ◽  
Atsushi Ono
Keyword(s):  
Finite Difference ◽  
Surface Plasmon ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Light Sensitivity ◽  
Silicon On Insulator ◽  
Electromagnetic Simulation ◽  
Metal Insulator ◽  
Difference Time

In order to improve the light sensitivity of silicon-on-insulator metal-insulator-semiconductor (SOI-MOS) photodiode, differences caused by the adhesion materials for gold (Au) line-and-space (L/S) surface plasmon (SP) antenna in MOS structure are evaluated based on the electromagnetic simulation using finite difference time domain (FDTD) method.

scholarly journals The Interference Pattern of Plasmonic and Photonic Modes Manipulated by Slit Width

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 730
Author(s):  
Xing Li ◽  
Jing Tang ◽  
Xuelian Zhang ◽  
Ruirui Zhang ◽  
Xiangyu Zeng ◽  
...  
Keyword(s):  
Finite Difference ◽  
Interference Pattern ◽  
Intensity Distribution ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Imaging System ◽  
Slit Width ◽  
Experimental Results ◽  
Far Field ◽  
Difference Time

We demonstrate that the interference pattern of the plasmonic and photonic modes can be controlled by changing the slit width of a square slit structure. Based on the analyses of the plasmonic and photonic modes of slits with different widths, we theoretically derived the expressions of wavefield generated by a square slit. A far-field scattered imaging system is utilized to collect the intensity distribution experimentally. Various interference patterns, including stripes, square-like lattice array, and diamond-like lattice array, have been observed by adjusting the slit widths. In addition, the results were validated by performing finite-difference time-domain simulations, which are consistent with the theoretical and experimental results.

scholarly journals Optimized 3D Finite-Difference-Time-Domain Algorithm to Model the Plasmonic Properties of Metal Nanoparticles with Near-Unity Accuracy

Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 114
Author(s):  
Mehran Rafiee ◽  
Subhash Chandra ◽  
Hind Ahmed ◽  
Sarah J. McCormack
Keyword(s):  
Optical Properties ◽  
Finite Difference ◽  
Metal Nanoparticles ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Experimental Results ◽  
Fdtd Simulation ◽  
Localized Surface Plasmon ◽  
Difference Time

The finite difference time domain (FDTD) method is a grid-based, robust, and straightforward method to model the optical properties of metal nanoparticles (MNPs). Modelling accuracy and optical properties can be enhanced by increasing FDTD grid resolution; however, the resolution of the grid size is limited by the memory and computational requirements. In this paper, a 3D optimized FDTD (OFDTD) was designed and developed, which introduced new FDTD approximation terms based on the physical events occurring during the plasmonic oscillations in MNP. The proposed method not only required ~52% less memory than conventional FDTD, but also reduced the calculation requirements by ~9%. The 3D OFDTD method was used to model and obtain the extinction spectrum, localized surface plasmon resonance (LSPR) frequency, and the electric field enhancement factor (EF) for spherical silver nanoparticles (Ag NPs). The model’s predicted results were compared with traditional FDTD as well as experimental results to validate the model. The OFDTD results were found to be in excellent agreement with the experimental results. The EF accuracy was improved by 74% with respect to FDTD simulation, which helped reaching a near-unity OFDTD accuracy of ~99%. The λLSPR discrepancy reduced from 20 nm to 3 nm. The EF peak position discrepancy improved from ±5.5 nm to only ±0.5 nm.

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