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1

Measurement of the surface reflectance of an acoustic wave using wave packets propagating in a circular waveguide

Wrzeciono Piotr, Szymański Michał

Vibrations in Physical Systems

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2022

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Vol. 33, nr 2

art. no. 2022218

EN

The main idea of the measurement presented in this paper was to separate the incident wave from the reflected wave. For this purpose, short wave packets and a sufficiently long waveguide with a circular cross-section were used. Several types of wave packets were developed and used in the experiment. We found that a wave packet of 5 ms duration could be propagated in a waveguide of length 5.6 meters without significant sound level losses. We used an audio interface operating at a sampling rate of 96 kHz in the measurements. The limit of wave propagation without dispersion phenomenon was determined. The developed measurement methodology made it possible to maintain the same air temperature along the entire length of the tested waveguide since short pulses did not cause the speaker temperature to rise. Avoiding this effect reduced the measurement uncertainty of the reflection coefficient.

2

Four channel optical demultiplexer based on L2 photonic crystal microcavity

Ammari Merzoug, Benmerkhi Ahlem, Bouchemat Mohamed

Optica Applicata

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2022

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Vol. 52, nr 4

613--625

EN

The wavelength demultiplexing is a particularly important function in integrated optics and can be realized using photonic crystals. The aim is to extract accurately the wavelengths in a data flux. In this work, we investigate a new topologies of wavelength demultiplexing based on two-dimensional photonic crystals constituted of dielectric rods spread in a square network. The studied demultiplexer is based on optical filters with optimized parameters in order to extract four different wavelengths in the vicinity of frequencies corresponding to communication windows. It was found that the crosstalk between the structure channels of the demultiplexer are in the range of –19.19 and – 44.1 dB and the channel spacing is equal to 0.96 nm. The simulation results presented in this paper are performed and analyzed using the FDTD method.

3

2D Modeling of Wave Propagation in Shallow Water by the Method of Characteristics

Khalilabadi Mohammad Reza

Archives of Acoustics

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2022

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Vol. 47, No. 3

407--412

EN

In this paper, a 2D numerical modeling of sound wave propagation in a shallow water medium that acts as a waveguide, are presented. This modeling is based on the method of characteristic which is not constrained by the Courant–Friedrichs–Lewy (CFL) condition. Using this method, the Euler time-dependent equations have been solved under adiabatic conditions inside of a shallow water waveguide which is consists of one homogeneous environment of water over a rigid bed. In this work, the stability and precision of the method of characteristics (MOC) technique for sound wave propagation in a waveguide were illustrated when it was applied with the semi-Lagrange method. The results show a significant advantage of the method of characteristics over the finite difference time domain (FDTD) method.

4

A six-port measurement device for high power microwave vector network analysis

Kommey Benjamin, Addo Ernest Ofosu, Tamakloe Elvis, Tchao Eric Tutu, Nunoo-Mensah Henry, Akowuah Bright Yeboah

Applied Computer Science

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2022

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Vol. 18, no 3

105--129

EN

The changes experienced in technology due to the third industrial revolution have over the years contributed immensely to the development of efficient devices and systems. As a result, solutions have been provided to challenges encountered in the heating industry. However, higher efficiency and better performance has undoubtedly been highly sort after. This paper presents the complete industrial development of a new system of a microwave device for use in S-band networks (2.45 GHz ISM band in this application): a vector network analyzer (VNA). The VNA, which is designed based on the six-port measurement principle, provides accurate measurements of both magnitude and phase of the load reflection coefficient. The device is designed to have high power handling capabilities and works under the full operating conditions of high-power microwave generators. Initial measurements show that the device perform stable and can perform temperature-independent measurements over protracted periods. The system is suited for on-line monitoring and control of network parameters in industrial waveguide applications.

5

A review of the current state-of-the-art in Fano resonance-based plasmonic metal-insulator-metal waveguides for sensing applications

Adhikari R., Chauhan D., Mola G. T., Dwivedi R. P.

Opto-Electronics Review

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2021

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Vol. 29, No. 4

148--166

EN

Fano resonance is an optical effect that emerges from the coherent coupling and interference (constructive and destructive) between the continuous state (background process) and the Lorentzian state (resonant process) in the plasmonic waveguide-resonator system. This effect has been used in the applications like optical sensors. These sensors are extensively used in sensing biochemicals and gases by the measurement of refractive index changes as they offer high sensitivity and ultra-high figure of merit. Herein, we surveyed several plasmonic Fano sensors with different geometries composed of metal-insulator-metal waveguide(s). First, the resonators are categorized based on different architectures. The materials and methods adopted for these designs are precisely surveyed and presented. The performances are compared depending upon the characterization parameters like sensitivity and figure of merit. Finally, based on the survey of very recent models, the advances and challenges of refractive index sensing deployed on Fano resonances are discussed.

6

Influence of InGaN waveguide on injection efficiency in III-nitride laser diodes

Hajdel Mateusz, Muzioł Grzegorz, Nowakowski-Szkudlarek Krzesimir, Siekacz Marcin, Wolny Paweł, Skierbiszewski Czesław

Optica Applicata

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2020

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Vol. 50, nr 2

311--321

EN

The influence of using InGaN waveguides on blue laser diodes was theoretically studied using 1D drift diffusion model and 2D optical mode calculation. Despite of the known effect of increased confinement of an optical mode, especially for long wavelengths, an unexpected influence on the efficiency of carrier injection into the active region is discussed. It is found that InGaN-AlGaN interface is crucial to achieving high injection efficiency. A numerical model is created, which describes the influence of InGaN waveguide and Mg doping of electron blocking layer on basic properties of laser diodes. It is found that an increase of injection efficiency allows to reduce the doping level in an electron blocking layer and take advantage of decreased optical losses.

7

Non-uniform Rectilinear Grid in the Waveguide Modeling of the Vocal Tract

Qureshi Tahir Mushtaq, Syed Khalid Saifullah, Zafar Asim

Archives of Acoustics

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2020

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Vol. 45, No. 4

585--600

EN

For many years, a digital waveguide model is being used for sound propagation in the modeling of the vocal tract with the structured and uniform mesh of scattering junctions connected by same delay lines. There are many varieties in the formation and layouts of the mesh grid called topologies. Current novel work has been dedicated to the mesh of two-dimensional digital waveguide models of sound propagation in the vocal tract with the structured and non-uniform rectilinear grid in orientation. In this work, there are two types of delay lines: one is called a smaller-delay line and other is called a larger-delay line. The larger-delay lines are the double of the smaller delay lines. The scheme of using the combination of both smaller- and larger-delay lines generates the non-uniform rectilinear two-dimensional waveguide mesh. The advantage of this approach is the ability to get a transfer function without fractional delay. This eliminates the need to get interpolation for the approximation of fractional delay and give efficient simulation for sound wave propagation in the two-dimensional waveguide modeling of the vocal tract. The simulation has been performed by considering the vowels /ɔ/, /a/, /i/ and /u/ in this work. By keeping the same sampling frequency, the standard two-dimensional waveguide model with uniform mesh is considered as our benchmark model. The results and efficiency of the proposed model have compared with our benchmark model.

8

An overview of different possibilities to master the challenge of coupling an ae-sensor to an object of interest partly using examples of previous investigations

Ziegler Burkhard, Dudzik Krzysztof

Journal of KONES

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2019

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Vol. 26, No. 1

207--214

EN

Acoustic emission analysis is defined as a passive, non-destructive investigation method, which only listens for AEwaves (AEW), generated actively by an object of interest. Therefore, the AEW must have the possibility to propagate from their source to an acoustic emission sensor (AES). By virtue of the piezoelectric effect, the AEW transmitted into electrical signals inside of the AES. During the analysation of these electrical signals we earn –online– information about the object of interest, e.g. the operating characteristic of a machine or the strength of the friction of a tribolocical system. To enable the AEW to propagate into the AES, the sensor has to be fixed suitable onto the object of interest. Hereby has to be strictly respected, that the sensor is fixed in a reproducible mechanical way as well as to ensure that the through-transmission has a weak attenuation (couplant). Standard AES have the shape of a circular cylinder (diameter and height depend on the operation purpose), the AEW pass through one of the frontends into the sensor. The objects of interest can have different geometry of the surface (e.g. plane, cylindrical, unspecific) or temperatures which usually conflicting the operating range of the sensor. Depending on the operational purpose, there are many different couplants to use. This article offers help to master the different connecting challenges within the range of acoustic emission analysis.

9

Crosstalk Noise Aware System For WDM-Based Optical Network on Chip

Jedidi Ahmed

International Journal of Electronics and Telecommunications

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2019

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Vol. 65, No. 3

497--505

EN

Network on chip (NoC) is presented as a promising solution to face off the growing up of the data exchange in the multiprocessor system-on-chip (MPSoC). However, the traditional NoC faces two main problems: the bandwidth and the energy consumption. To face off these problems, a new technology in MPSoC, namely, optical network-on-chip (ONoC) has been introduced which it uses the optical communication to guaranty a high performance in communication between cores. In addition, wavelength division multiplexing (WDM) is exploited in ONoC to reach a high rate of bandwidth. Nevertheless, the transparency nature of the ONoC components induce crosstalk noise to the optical signals, which it has a direct effect to the signal-to-noise ratio (SNR) then decrease the performance of the ONoC. In this paper, we proposed a new system to control these impairments in the network in order to detect and monitor crosstalk noise in WDM-based ONoC. Furthermore, the crosstalk monitoring system is a distributed hardware system designed and test with the different optical components according the various network topology used in ONoC. The register-transfer level (RTL) hardware design and implementation of this system can result in high reliability, scalability and efficiency with running time less than 20 ms.

10

Modeling of diffraction radiation processes on periodic metal-dielectric structures in millimeter wavelength range

Rybalko O., Zhurba V., Petrovskyi M., Rybalko I., Buriak I., Vorobyov G.

Optica Applicata

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2018

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Vol. 48, nr 1

105--116

EN

A general approach to experimental modeling of Cherenkov and diffraction radiation in vacuum electron devices employing periodic metal-dielectric structures is presented. The potential benefits and drawbacks of this approach to the design of microwave devices are discussed. The approach is based on resemblance of electromagnetic properties between the modulated electron beam and the surface wave in a dielectric waveguide. A dedicated millimeter-wave experimental setup is developed and constructed.

11

Design of a novel photonic crystal 1.31/1.55 µm bi-band filter for near infrared application

Lallam F., Badaoui H., Abri M., Fedaouche A.

Optica Applicata

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2018

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Vol. 48, nr 3

341--348

EN

A novel design of a double selective filter for integrated optics in two-dimensional photonic crystals operating at a wavelength of 1.31 and 1.55 µm is proposed in this paper. We focus particularly on filters transmission and selectivity enhancement. The two-dimensional photonic crystals filters are simulated by using a combination of three cascaded waveguides; these later are conceived by one missing row and with different rods radii for efficient filtering purpose. The properties of these photonic crystal structures are numerically investigated by using the two-dimensional finite-difference time-domain method and the numerical results are given for incident light wave having transverse electrical polarization. A final synthesized filter topology is presented and the maximum of transmission is found around 70% and 60% localized respectively near 1.31 and 1.55 µm wavelengths.

12

Performance analysis of two-dimensional photonic crystal octagonal ring resonator based eight channel demultiplexer

Kannaiyan V., Dhamodharan S. K., Savarimuthu R.

Optica Applicata

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2017

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Vol. 47, nr 1

7--18

EN

We proposed a high performance eight channel demultiplexer using two-dimensional photonic crystal octagonal ring resonator for wavelength division multiplexing applications. The performance parameters such as transmission efficiency, Q factor, spectral width, resonant wavelength, crosstalk and channel spacing of the proposed demultiplexers are evaluated. The plane wave expansion method manipulates photonic band gap of periodic and non-periodic structure. Finite-difference time-domain method is used to evaluate the performance parameters of designed two-dimensional photonic crystal structure. The proposed demultiplexer provides overall transmission efficiency, Q factor, spectral width of about 98%, 1968 and 0.8 nm, respectively. The ultra-compact eight channel demultiplexer performs better than the reported one. Hence this work can be implemented for real time applications.

13

Design and Optimization of Rectangular Waveguide Filter based on Direct Coupled Resonators

Damou M., Nouri K., Feham M., Chetioui M.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 4

375--380

EN

The waveguide filter structure is treated by two softwares (HFSS (High Frequency Structure Simulator) and CST (Computer Simulation Technology)). Numerical example is given in this article to demonstrate, step by step, the application of the approach to the design of resonator, direct coupled waveguide and microstrip filters based on electromagnetic (EM) simulations. For this design procedure, the filter structure is simulated by successively adding one resonator at a time. To continue the work illustrates how to design a fourth order coupled resonator based rectangular waveguide circuit in the traditional way. With a large number of variables, such tuning work consumes a lot of time and the convergence of the final result is not guaranteed. A fourth order X-band bandpass filter with a center frequency of 11 GHz and a fractional bandwidth FBW = 0,0273 is designed using this procedure and presented here as an example. The simulated results by CST are presented and compared withthe results simulated by a high-frequency structure simulator. Good agreement between the simulated HFSSand simulated results by CST is observed.

14

Open source ELMER software based FEM modeling of waveguides and resonant cavities for microwave heating and drying devices

Szałatkiewicz J., Szewczyk R., Kalinowski M., Kataja J., Råback P., Ruokolainen J., Kachniarz M.

Archives of Electrical Engineering

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2017

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Vol. 66, nr 4

745--750

EN

Microwave devices are widely used in the industry and in the specialized laboratory analyses. Development of such devices requires the possibility of modeling of microwave energy distribution in the specific resonant chambers. Until now, such modeling was possible only with the use of commercial software or was limited to specific cases. The paper presents an open-source module for ELMER software for solving timeharmonic Maxwell’s equations, allowing modeling of microwave waveguide lines. Three test cases of different resonant chambers are investigated at 2.45 GHz frequency. Modeling results obtained from the open-source ELMER Vectorial Helmholtz module show that the application of this software can be effective in R&D works, enabling high-tech small and medium enterprises involvement in advanced microwave technology.

15

Analiza falowodów ze związków InGaAs, InAlAs i InP dla laserów kaskadowych emitujących w zakresie średniej podczerwieni

Pruszyńska-Karbownik E., Gutowski P., Karbownik P., Sankowska I., Bugajski M.

Elektronika : konstrukcje, technologie, zastosowania

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2016

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Vol. 57, nr 9

23--27

PL

W pracy przedstawiono wyniki obliczeń numerycznych falowodów laserów kaskadowych emitujących promieniowanie o długości fali ok. 5 μm. Rozważano niesymetryczne falowody zawierające podłoże z InP oraz warstwy InGaAs i InAlAs dopasowane sieciowo do InP projektowane do wytworzenia poprzez wzrost epitaksjalny przy wykorzystaniu wyłącznie epitaksji z wiązek molekularnych (MBE). Wyznaczono teoretyczne wartości współczynnika przekrycia pola elektrycznego i obszaru czynnego oraz strat modów poprzecznych dla różnych grubości poszczególnych warstw falowodowych oraz ilości periodów obszaru czynnego. Uzyskane wyniki obliczeń zostały zweryfikowane dla jednej z rozważanych konstrukcji falowodu poprzez porównanie wyznaczonego teoretycznego rozkładu promieniowania w polu dalekim z rozkładem wyznaczonym eksperymentalnie przy użyciu szerokokątnego profilometru goniometrycznego. Względna różnica pomiędzy szerokościami połówkowymi rozkładów teoretycznego i doświadczalnego wyniosła 3,5%.

EN

In this paper, we present results of numerical calculations of quantum cascade laser waveguides emitting radiation with a wavelength of approx. 5 μm. Asymmetric waveguides containing InP substrate and InGaAs and InAlAs lattice matched to InP have been considered. The waveguides have been designed to be manufactured by using molecular beam epitaxy (MBE). We have determined theoretical values of confinement factor and loss of transverse modes for different thicknesses of each waveguide layer. The results of calculations have been verified for one waveguide design by comparing calculated far-field distribution with experimental distribution measured by using a wide-angle goniometric profiler. The relative difference between full width at half maximum of both distributions is 3,5%.

16

Technologia LP-MOVPE heterostruktur InGaAs/InP do konstrukcji kwantowych laserów kaskadowych

Badura M., Bielak K., Ściana B., Radziewicz D., Pucicki D., Dawidowski W., Tłaczała M.

Elektronika : konstrukcje, technologie, zastosowania

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2014

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Vol. 55, nr 11

34-36

PL

Kwantowe lasery kaskadowe (QCLs), tzw. lasery unipolarne, które emitują fale o długości z zakresu okna atmosferycznego 3…5 μm, wymagają zastosowania układu materiałowego o dużej nieciągłości pasma przewodnictwa i bardzo dobrej przewodności cieplnej. Wymagania te spełnia układ materiałowy InGaAs/AlInAs/InP. W pracy przedstawiono wyniki badań związanych z epitaksją związków potrójnych InGaAs, dopasowanych sieciowo do InP, przy zastosowaniu niskociśnieniowej metody MOVPE. Pierwszym etapem badań było opracowanie kinetyki wzrostu niedomieszkowanych warstw In- GaAs, dopasowanych sieciowo do InP. Otrzymane warstwy wykazały bardzo dobre właściwości optyczne, co zostało potwierdzone wynikami pomiarów fotoluminescencji. Morfologia tych warstw, badana przy użyciu mikroskopu AFM, wykazała tarasowy wzrost typu „step-flow” i atomową gładkość powierzchni. Kolejnym etapem prowadzonych badań są prace technologiczne związane z domieszkowaniem heterostruktury InGaAs/InP krzemem.

EN

Quantum cascade lasers (QCL) so-called unipolar lasers, which emit light with wavelength at range of atmospheric window 3÷5 μm, require construction from the material system with sufficient conduction band discontinuity and high thermal conductivity. Such requirements are fulfilled by InGaAs/AlInAs/InP. In these paper are shown results of investigation of metalorganic vapor phase epitaxy of ternary alloy InGaAs lattice matched to InP. Grown layers have good optical properties, what is confirmed by photoluminescence measurements. Surface morphology of described samples tested by AFM exhibits step-flow growth and atomic scale surface smoothness. The next stage of ours research will be focused on n-type doping of InGaAs/InP heterostructure with SiH4 as a dopant source.

17

Macromodels for Efficient FEM Simulation of Waveguides and Resonators

Fotyga G., Nyka K., Kulas Ł.

Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne

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2010

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T. 18

375-378

EN

This paper introduces a novel technique for enhancing the efficiency of the finite element method (FEM) by incorporating special modules, called macromodels, into the standard eigenvalue formulation. The number of unknowns in the separated macromodel subdomain can be significantly reduced by orthogonal projection, using the efficient nodal order reduction algorithm. The idea of macromodels implementation is demonstrated on a simple one-dimensional numerical example. High accuracy and efficiency make it a promising methodology for further developments.

PL

Artykuł opisuje innowacyjną technikę poprawy efektywności metody elementu skończonego poprzez włączanie do standardowego sformułowania własnego specjalnych modułów, zwanych makromodelami. Liczba zmiennych w wydzielonej podprzestrzeni może być znacznie zredukowana poprzez zastosowanie algorytmu ENOR, tworzącego bazę ortogonalną. Koncepcja makromodeli jest przedstawiona w oparciu o jednowymiarowy, prosty przypadek. Duża dokładność i efektywność sprawiają, że algorytm ten może być z powodzeniem rozwijany w przyszłości.

18

Wielowiązkowy układ do obserwacji ugięcia dźwigni macierzy czujników mikromechanicznych

Małozięć G., Gotszalk T., Nieradka K., Wielgoszewski G., Sulecki P., Radojewski J., Grabiec P., Janus P.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 10

83-85

PL

W pracy przedstawiono układ do pomiaru statycznego wychylenia oraz charakterystyk rezonansowych mikrodźwigni sprężystych zintegrowanych w jednowymiarowej macierzy. Opisano budowę stanowiska do sterowania laserami półprzewodnikowymi oraz stabilizacji ich temperatury.

EN

In the paper set-up to measure static deflection and resonance characteristics of cantilevers was presented. The cantilevers was integrated in one-dimension matrix. Construction of semiconductor lasers control station and temperature controller was described.

19

THz/sub-THz bolometer based on electron heating in a semiconductor waveguide

Dobrovolsky V., Sizov F.

Opto-Electronics Review

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2010

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Vol. 18, No. 3

250-258

EN

Direct detection THz/sub-THz bolometer is proposed. In it an electromagnetic wave propagates in the bipolar semiconductor waveguide, heats electrons and holes there, and therefore creates their bipolar thermodiffusion flow and, as well as, the electromotive force (emf). The flow causes the carrier excess concentration. Both this concentration and emf are used to get the bolometer response voltage. The bolometer theoretical model is developed. The possibility without cooling or moderate cooling (about 100 K for the Cd₀.₂Hg₀.₈Te bolometers) to get acceptable for applications values of the noise equivalent power is shown. Experimental results confirm the main model conclusions.

20

A 60° photonic crystal waveguide bend with improved transmission characteristics

Moghaddam M. K., Mirsalehi M. M., Attari A. R.

Optica Applicata

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2009

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Vol. 39, nr 2

307-317

EN

In this paper, a 60° waveguide bend is designed in a two-dimensional (2D) photonic crystal (PC) slab to provide high transmission over a large bandwidth. We apply geometrical modification in the bend region to improve the transmission characteristics. This modification results in increasing the relative bandwidth from 6.5% to 25.7% of photonic band gap width. Using the effective refractive index, the structures designed are simulated by the 2D finite-difference time-domain (FDTD) method. As a specific application, we use the improved bend structure in a PC waveguide directional coupler and show that the drop output increases significantly.