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Analysis and simulation of ring resonator silicon electro-optic modulators based on PN junction in reverse bias
, Article Optical Engineering ; Vol. 53, issue. 12 , 2014 ; ISSN: 00913286 ; Akbari, M ; Sharif University of Technology
Abstract
The theory of silicon optical modulators of ring resonators based on PN diode in reverse bias is primarily discussed. It secondarily provides a full-featured simulator to investigate the behavior of such modulators. Wave equation for ring structure will be solved by using the conformal transformation method and the matrix method as it was used to analyze bent planar optical waveguides. Power coupling between ring and straight waveguides will be calculated by coupled theory of nonparallel waveguides based on experimental results. The time response demonstrates the capability of this device to operate correctly at up to 10 Gbs-1 bitrate, and the frequency spectrum analysis of device shows a >...
Fast fourier transform based NDT approach for depth detection of hidden defects using HTS rf-SQUID
, Article IEEE Transactions on Applied Superconductivity ; Volume 28, Issue 7 , 2018 ; 10518223 (ISSN) ; Shanehsazzadeh, F ; Fardmanesh, M ; Sharif University of Technology
Abstract
We present a new approach for depth detection of hidden defects based on the analysis of the frequency spectrum of the output waveform in a nondestructive testing (NDT) system. In our eddy current Superconducting quantum interference device (SQUID) based NDT system, we apply multiple frequencies to its single excitation coil in a magnetically unshielded environment. The excitation coil is a planar D-shaped printed circuit board coil, and a high-Tc gradiometer YBCO rf-SQUID is used as the electromagnetic sensor in this system. An automated two-dimensional nonmagnetic scanning robot is used to test samples with intentional defects at different depths. In this approach, a diagram labeled 'FFT...