A Broadband Polarization-Insensitive Graphene Modulator Based on Dual Built-in Orthogonal Slots Plasmonic Waveguide

A broadband polarization-insensitive graphene modulator has been proposed. The dual built-in orthogonal slots waveguide allows polarization independence for the transverse electric (TE) mode and the transverse magnetic (TM) mode. Due to the introduction of metal slots in both the vertical and horizontal directions, the optical field as well as the electro-absorption of graphene are enhanced by the plasmonic effect. The proposed electro-optic modulator shows a modulation depth of 0.474 and 0.462 dB/μm for two supported modes, respectively. An ultra-low effective index difference of 0.001 can be achieved within the wavelength range from 1100 to 1900 nm. The 3 dB-bandwidth is estimated to be 101 GHz. The power consumption is 271 fJ/bit at a modulation length of 20 μm. The proposed modulator provides high speed broadband solutions in microwave photonic systems.

Download Full-text

The magnetotelluric transverse electric mode as a natural filter for static effects: Application to the COPROD2 and COPROD2S2 data sets

Geophysics ◽

10.1190/geo2012-0522.1 ◽

2014 ◽

Vol 79 (2) ◽

pp. E91-E99 ◽

Cited By ~ 3

Author(s):

Enrique Gómez-Treviño ◽

Francisco J. Esparza ◽

Yunuhen Muñiz ◽

Armando Calderón

Keyword(s):

Electromagnetic Induction ◽

Transverse Electric ◽

Transverse Magnetic ◽

Data Sets ◽

Data Set ◽

Te Mode ◽

Tm Mode ◽

Amplitude Data ◽

Final Interpretation ◽

Electric Mode

We regard the amplitude of the magnetotelluric impedance of the transverse electric (TE) mode as output, rather than input, in 2D inverse algorithms. The model obtained in the inversion is in this context only an intermediate product whose TE theoretical response is for all intents and purposes the object of the inversion. The input is the amplitude of the transverse magnetic (TM) mode and the phases of both modes. They are fitted as much as possible by relaxing regularization to its limits, allowing the model to include features not strictly required by the data, but still required by the amplitude of the TE curves. We propose two tests to guaranty the accuracy and reliability of the recovery. The first is a convergence test whereby the output is monitored as a function of the roughness of the model. Second, the TM amplitude data are multiplied by different factors and the output is checked for consistency with the previous test. The resulting TE responses have only electromagnetic induction effects and thus are free from static shifts due to electric charges. We apply the procedure to the synthetic COPROD2S2 data set and compute static factors for TE and TM modes. We propose an image based on depth averages of conductivity along with a nonlinear resolution-variance analysis of the image as the final interpretation of the data. The procedure is also applied to the well-known COPROD2 field data set.

Download Full-text

Modelling of Terrain Effect from the Magnetotelluric (MT) Field Data

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.b7756.129219 ◽

2019 ◽

Vol 9 (2) ◽

pp. 5059-5062

Keyword(s):

Finite Difference ◽

Rayleigh Scattering ◽

Transverse Electric ◽

Transverse Magnetic ◽

Impedance Tensor ◽

Topographic Features ◽

Te Mode ◽

Tm Mode ◽

Terrain Effect ◽

Computation Algorithm

Magnetotelluric (MT) data were recorded over highly undulating terrain in Himalayan region from Roorkee to Gangotri section in period 0.001-1000 second. In the presence of topographic distortion the interpretation may become misleading. A simple scheme based on finite difference method for the simulation of the topographic distortion in magnetotelluric response is presented. The finite difference based, forward response computation algorithm, has been extended for undulating topography. The distortion coefficients, representing the topographic effect, are designed for correcting the observed distorted impedance tensor recorded in the vicinity of topographic features. The accuracy of the scheme is checked by comparing the computed responses with the finite element, Rayleigh scattering and transmission surface results for transverse electric (TE-mode) and transverse magnetic (TM-mode) responses. The modified algorithm is used to model the terrain effect on MT data recorded from Himalayan terrain.

Download Full-text

10 nm SiO2 TM Slot Mode in Laterally Mismatched Asymmetric Fin-Waveguides

Frontiers in Physics ◽

10.3389/fphy.2021.659585 ◽

2021 ◽

Vol 9 ◽

Author(s):

James Byers ◽

Kapil Debnath ◽

Hideo Arimoto ◽

Muhammad K. Husain ◽

Moïse Sotto ◽

...

Keyword(s):

Transverse Electric ◽

Mode Conversion ◽

Transverse Magnetic ◽

Silicon On Insulator ◽

Si Photonics ◽

Te Mode ◽

Tm Mode ◽

Transmission Data ◽

Fdtd Simulations ◽

Difference Time

In this paper we demonstrate that by breaking the left/right symmetry in a bi-planar double-silicon on insulator (SOI) photonic crystal (PhC) fin-waveguide, we can couple the conventionally used transverse-electric (TE) polarized mode to the transverse-magnetic (TM) polarization slot-mode. Finite difference time domain (FDTD) simulations indicate that the TE mode couples to the robust TM mode inside the Brillouin zone. Broadband transmission data shows propagation identified with horizontal-slot TM mode within the TE bandgap for fully mismatched fabricated devices. This simultaneously demonstrates TE to TM mode conversion, and the narrowest Si photonics SiO2 slot-mode propagation reported in the literature (10 nm wide slot), which both have many potential telecommunication applications.

Download Full-text

A New Method to Verify the Measurement Speed and Accuracy of Frequency Modulated Interferometers

Applied Sciences ◽

10.3390/app11135787 ◽

2021 ◽

Vol 11 (13) ◽

pp. 5787

Author(s):

Toan-Thang Vu ◽

Thanh-Tung Vu ◽

Van-Doanh Tran ◽

Thanh-Dong Nguyen ◽

Ngoc-Tam Bui

Keyword(s):

Phase Change ◽

High Speed ◽

Measurement Accuracy ◽

Slow Motion ◽

New Method ◽

Virtual Displacement ◽

Electro Optic ◽

Lock In ◽

Speed And Accuracy ◽

Electro Optic Modulator

The measurement speed and measurement accuracy of a displacement measuring interferometer are key parameters. To verify these parameters, a fast and high-accuracy motion is required. However, the displacement induced by a mechanical actuator generates disadvantageous features, such as slow motion, hysteresis, distortion, and vibration. This paper proposes a new method for a nonmechanical high-speed motion using an electro-optic modulator (EOM). The method is based on the principle that all displacement measuring interferometers measure the phase change to calculate the displacement. This means that the EOM can be used to accurately generate phase change rather than a mechanical actuator. The proposed method is then validated by placing the EOM into an arm of a frequency modulation interferometer. By using two lock-in amplifiers, the phase change in an EOM and, hence, the corresponding virtual displacement could be measured by the interferometer. The measurement showed that the system could achieve a displacement at 20 kHz, a speed of 6.08 mm/s, and a displacement noise level < 100 pm//√Hz above 2 kHz. The proposed virtual displacement can be applied to determine both the measurement speed and accuracy of displacement measuring interferometers, such as homodyne interferometers, heterodyne interferometers, and frequency modulated interferometers.

Download Full-text

Single-Source Duplex High-Speed FSO Communications Using Electro-Optic Modulator-Based MRR

Conference on Lasers and Electro-Optics ◽

10.1364/cleo_at.2018.jtu2a.54 ◽

2018 ◽

Cited By ~ 1

Author(s):

Xianglian Feng ◽

Hexin Jiang ◽

Zhihang Wu ◽

Tianshu Wang ◽

Hongwei He ◽

...

Keyword(s):

High Speed ◽

Single Source ◽

Electro Optic ◽

Electro Optic Modulator

Download Full-text

Quad-Band Plasmonic Perfect Absorber for Visible Light with a Patchwork of Silicon Nanorod Resonators

Materials ◽

10.3390/ma11101954 ◽

2018 ◽

Vol 11 (10) ◽

pp. 1954 ◽

Cited By ~ 11

Author(s):

Can Cao ◽

Yongzhi Cheng

Keyword(s):

Visible Light ◽

Transverse Electric ◽

Transverse Magnetic ◽

Localized Surface Plasmon ◽

Perfect Absorber ◽

Absorption Properties ◽

Perfect Absorption ◽

Potential Applications ◽

Polarization Insensitive ◽

Band Absorption

In this paper, a plasmonic perfect absorber (PPA) based on a silicon nanorod resonator (SNRR) for visible light is proposed and investigated numerically. The proposed PPA is only a two-layer nanostructure consisting of a SNRR periodic array and metal substrate. The perfect absorption mainly originates from excitation of the localized surface plasmon resonance (LSPR) mode in the SNRR structure. The absorption properties of this design can be adjusted by varying the radius (r) and height (h) of the SNRR structure. What is more, the stronger quad-band absorption can be achieved by combing four different radius of the SNRR in one period as a super unit-cell. Numerical simulation indicates that the designed quad-band PPA can achieve the absorbance of 99.99%, 99.8%, 99.8%, and 92.2% at 433.5 THz, 456 THz, 482 THz, and 504.5 THz, respectively. Further simulations show that the proposed PPA is polarization-insensitive for both transverse electric (TE) and transverse magnetic (TM) modes. The proposed PPA can be a desirable candidate for some potential applications in detecting, sensing, and visible spectroscopy.

Download Full-text

Integrated (Pb,La)(Zr,Ti)O3 Heterostructure Waveguide Devices Fabricated by Solid-Phase Epitaxy

MRS Proceedings ◽

10.1557/proc-597-151 ◽

1999 ◽

Vol 597 ◽

Cited By ~ 2

Author(s):

K. Nashimoto ◽

S. Nakamura ◽

H. Moriyama ◽

K. Haga ◽

M. Watanabe ◽

...

Keyword(s):

Low Voltage ◽

Solid Phase ◽

Wet Etching ◽

Propagation Loss ◽

Beam Deflection ◽

Solid Phase Epitaxy ◽

Te Mode ◽

Tm Mode ◽

Electro Optic ◽

Channel Waveguides

AbstractHeterostructures of a Pb(Zr,Ti)O3 (PZT) waveguide/(Pb,La)(Zr,Ti)O3 (PLZT) system buffer layer were grown on a Nb-doped SrTiO3 (Nb:ST) substrate by solid-phase epitaxy. The propagation loss in the PLZT heterostructure waveguides was on the order of I dB/cm. An electro-optic beam deflection device with an ITO prism electrode on the surface of the PLZT heterostructure waveguide presented efficient deflection of the coupled laser beam by applying a voltage between the electrode and the substrate. A beam deflection greater than 10 mrad at 5 V and frequency response as fast as 13 MHz were observed. An apparent electro-optic coefficient as large as 39 pmJV was estimated from the deflection characteristics for the TE mode and TM mode suggesting the polarization independent nature of the PZT waveguide. For integrating the electrooptic PLZT heterostructure waveguides, channel waveguides were fabricated in the PZT waveguides using a simple wet-etching process. Based on a low-voltage drive structure, lowloss waveguide process, and fine patterning process, a fabricated digital matrix switch showed a – 10 dB cross-talk at a voltage as low as 7.5 V.

Download Full-text