TRANSFORMATION OF DIRECTIONAL COUPLERS TO MULTI-MODE INTERFEROMETERS BASED ON RIDGE WAVEGUIDES AND ITS APPLICATIONS

2005 ◽  
Vol 14 (02) ◽  
pp. 221-235 ◽  
Author(s):  
S. DARMAWAN ◽  
S. Y. LEE ◽  
C. W. LEE ◽  
M. K. CHIN
Keyword(s):  
Design Parameters ◽  
Large Set ◽  
Directional Couplers ◽  
Design Variables ◽  
Ridge Waveguides ◽  
Polarization Insensitive ◽  
Index Contrast ◽  
High Index Contrast ◽  
Coupling Characteristic ◽  
Multi Mode

We present a comparison of directional couplers and multi-mode interferometers based on the unique properties of high-index contrast ridge waveguides. The two devices are intimately related as the MMI is structurally derived from the DC. For the first time, the continuous evolution from the two-mode coupling characteristic of DC to the multi-mode mixing and interference characteristic of MMI is shown. We show that practical directional couplers with reasonable gap size can also be quite compact and have the same coupling length for both TE and TM polarizations. Consequently, the DC can be just as polarization insensitive as the MMI. These features, however, require careful design control involving a large set of design parameters. On top of that, we also show a novel design of polarization splitter based on both DC and MMI. By comparison, the MMI design is more robust and involves fewer design variables.

Polarization-Insensitive High-Index Contrast Gratings Beam Splitter With Focusing Ability

2018 ◽  
Vol 30 (8) ◽  
pp. 708-711 ◽  
Author(s):  
Wenjing Fang ◽  
Xinye Fan ◽  
Xia Zhang ◽  
Huijuan Niu ◽  
Hengying Xu ◽  
...  
Keyword(s):  
Beam Splitter ◽  
High Index ◽  
Polarization Insensitive ◽  
Index Contrast ◽  
High Index Contrast

scholarly journals Silicon Integrated Nanophotonic Devices for On-Chip Multi-Mode Interconnects

2020 ◽  
Vol 10 (18) ◽  
pp. 6365
Author(s):  
Hongnan Xu ◽  
Daoxin Dai ◽  
Yaocheng Shi
Keyword(s):  
Large Scale ◽  
Silicon On Insulator ◽  
Nanophotonic Devices ◽  
Mode Division Multiplexing ◽  
Higher Order Modes ◽  
Index Contrast ◽  
High Index Contrast ◽  
On Chip ◽  
Multi Mode ◽  
Development Prospects

Mode-division multiplexing (MDM) technology has drawn tremendous attention for its ability to expand the link capacity within a single-wavelength carrier, paving the way for large-scale on-chip data communications. In the MDM system, the signals are carried by a series of higher-order modes in a multi-mode bus waveguide. Hence, it is essential to develop on-chip mode-handling devices. Silicon-on-insulator (SOI) has been considered as a promising platform to realize MDM since it provides an ultra-high-index contrast and mature fabrication processes. In this paper, we review the recent progresses on silicon integrated nanophotonic devices for MDM applications. We firstly discuss the working principles and device configurations of mode (de)multiplexers. In the second section, we summarize the multi-mode routing devices, including multi-mode bends, multi-mode crossings and multi-mode splitters. The inverse-designed multi-mode devices are then discussed in the third section. We also provide a discussion about the emerging reconfigurable MDM devices in the fourth section. Finally, we offer our outlook of the development prospects for on-chip multi-mode photonics.

scholarly journals Transformation between directional couplers and multi-mode interferometers based on ridge waveguides

2004 ◽  
Vol 12 (14) ◽  
pp. 3079 ◽  
Author(s):  
Shuh-Ying Lee ◽  
Stevanus Darmawan ◽  
Chee-Wei Lee ◽  
Mee-Koy Chin
Keyword(s):  
Directional Couplers ◽  
Ridge Waveguides ◽  
Multi Mode

scholarly journals Stress Induced Effects for Advanced Polarization Control in Silicon Photonics Components

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
D.-X. Xu ◽  
W. N. Ye ◽  
S. Janz ◽  
A. Delâge ◽  
P. Cheben ◽  
...  
Keyword(s):  
Silicon On Insulator ◽  
Ring Resonators ◽  
Design Strategies ◽  
Arrayed Waveguide Gratings ◽  
Polarization Control ◽  
Waveguide Components ◽  
Polarization Insensitive ◽  
Index Contrast ◽  
High Index Contrast ◽  
Arrayed Waveguide

We review the use of the oxide cladding stress-induced photoelastic effect to modify the polarization dependent properties in silicon-on-insulator (SOI) waveguide components, and highlight characteristics particular to this high index contrast (HIC) systems. The birefringence in SOI waveguides has its origin in the electromagnetic boundary conditions at the waveguide boundaries, and can be further modified by the presence of stress in the waveguiding materials. With typical stress levels in SiO2 films, which are often used as the upper cladding, the waveguide effective index can be altered anisotropically up to the order of 10−3 for ridges with heights ranging from 1 μm to 5 μm. This effect can be used effectively to counter the waveguide geometrical birefringence, allowing the waveguide cross-section profiles to be optimized for design criteria other than null geometrical birefringence. Design strategies are developed for using stress engineering to achieve a variety of functions. Polarization insensitive arrayed waveguide gratings (AWGs), polarization insensitive ring resonators, and polarization splitters and filters are demonstrated using these design principles.

High Index-Contrast Silicon-On-Insulator Nanophotonics

2006 ◽  
Author(s):  
P. Bienstman ◽  
F. Laere ◽  
D. Taillaert ◽  
P. Dumon ◽  
W. Bogaerts ◽  
...  
Keyword(s):  
High Index ◽  
Silicon On Insulator ◽  
Index Contrast ◽  
High Index Contrast

A unified framework for the design of low-complexity wavelet filters

2017 ◽  
Vol 15 (06) ◽  
pp. 1750054 ◽  
Author(s):  
Ameya K. Naik ◽  
Raghunath S. Holambe
Keyword(s):  
Feature Extraction ◽  
Compact Support ◽  
Low Complexity ◽  
Design Parameters ◽  
Unified Framework ◽  
Vanishing Moments ◽  
Wavelet Filters ◽  
Design Variables ◽  
Optimum Filter ◽  
Simulation Results

An outline is presented for construction of wavelet filters with compact support. Our approach does not require any extensive simulations for obtaining the values of design variables like other methods. A unified framework is proposed for designing halfband polynomials with varying vanishing moments. Optimum filter pairs can then be generated by factorization of the halfband polynomial. Although these optimum wavelets have characteristics close to that of CDF 9/7 (Cohen-Daubechies-Feauveau), a compact support may not be guaranteed. Subsequently, we show that by proper choice of design parameters finite wordlength wavelet construction can be achieved. These hardware friendly wavelets are analyzed for their possible applications in image compression and feature extraction. Simulation results show that the designed wavelets give better performances as compared to standard wavelets. Moreover, the designed wavelets can be implemented with significantly reduced hardware as compared to the existing wavelets.

CAD and Optimization of Helical Torsion Springs

1994 ◽  
Author(s):  
Sayed M. Metwalli ◽  
M. Alaa Radwan ◽  
Abdel Aziz M. Elmeligy
Keyword(s):  
Iterative Process ◽  
Minimum Weight ◽  
Design Parameters ◽  
Optimal Parameters ◽  
Direct Evaluation ◽  
Torsion Spring ◽  
Performance Requirements ◽  
Design Variables ◽  
Method Of Lagrange Multipliers ◽  
Torsion Springs

Abstract The convensional procedure of helical torsion spring design is an iterative process because of large number of requirements and relations that are to be attained once at a time. The design parameters are varied at random until the spring design satisfies performance requirements. A CAD of the spring for minimum weight is formulated with and without the variation of the maximum normal stress with the wire diameter. The CAD program solves by employing the method of Lagrange-Multipliers. The optimal parameters, in a closed form are obtained, normalized and plotted. These explicit relations of design variables allow direct evaluation of optimal design objective and hence, an absolute optimum could be achieved. The comparison of optimum results with those previously published, shows a pronounced achievement in the reduction of torsion spring weight.

A Study on Optimum Design Using Fuzzy Numbers As Design Variables

1995 ◽  
Author(s):  
Masao Arakawa ◽  
Hiroshi Yamakawa
Keyword(s):  
Fuzzy Sets ◽  
Optimum Design ◽  
Fuzzy Numbers ◽  
Fuzzy Optimization ◽  
Design Parameters ◽  
Numerical Examples ◽  
Design Variables ◽  
Conventional Methods

Abstract In this study, we summerize the method of fuzzy optimization using fuzzy numbers as design variables. In order to detect flaw in fuzzy calculation, we use LR-fuzzy numbers, which is known as its simplicity in calculation. We also use simple fuzzy numbers’ operations, which was proposed in the previous papers. The proposed method has unique characteristics that we can obtain fuzzy sets in design variables (results of the design) directly from single numerical optimizing process. Which takes a large number of numerical optimizing processes when we try to obtain similar results in the conventional methods. In the numerical examples, we compare the proposed method with several other methods taking imprecision in design parameters into account, and demonstrate the effectiveness of the proposed method.

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