Jozef Chovan

Jozef Chovan
International Laser Center

Ing., PhD.

About

58
Publications
19,963
Reads
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95
Citations

Publications

Publications (58)
Article
Progress in integrated photonics enables development of photonics integrated circuits (PIC) with new unique properties and overcomes current limits in information and communication technologies. The effective coupling of optical radiation between telecom optical fiber and photonic integrated circuits is necessary. To address these challenges, we pr...
Conference Paper
Full-text available
This paper presents design, simulation and optimization of 1x8 Y-branch power splitters based on Si/SiO2/SiN/SiOx material platform. For the designs, two different waveguide structures were used, i.e. ridge and rib waveguides. The splitters were designed for 850 nm spectral optical window and the simulations were performed applying FEM and BPM meth...
Conference Paper
Full-text available
We present design and simulation of 16-channel, 100-GHz silicon nitride based AWG using BeamPROP simulation engine of RSoft photonic tool. The AWG was designed for TM-polarized light with central wavelength of 850 nm. The input design parameters were calculated applying AWG-Parameters tool. For this purpose, we created a ridge waveguide structure,...
Poster
MOTIVATION We present design and simulation of 16-channel, 100-GHz silicon nitride based AWG using BeamPROP simulation engine of RSoft photonic tool. The AWG was designed for TM-polarized light with central wavelength of 850 nm. The input design parameters were calculated applying AWG-Parameters tool. For this purpose, we created a ridge waveguide...
Conference Paper
Full-text available
This paper presents design and simulation of 8-channel, 100-GHz AWGs based on Si/SiO2/SiN/SiOx material platform. For the designs, two different waveguide structures were used, i.e. ridge and rib waveguides. AWGs were designed for central wavelength of 850 nm applying AWG-Parameters tool. The simulations were performed applying FEM and BPM methods...
Conference Paper
We present simulation of 8-channel, 100-GHz silicon nitride based AWGs using three different commercial photonics tools, namely PHASAR from Optiwave Systems Inc., APSS from Apollo Photonics Inc. and RSoft from Synopsys Inc. For this purpose we created identical waveguide structures and identical AWG layouts in these tools and performed BPM simulati...
Conference Paper
We present design and simulation of the low loss silicon nitride based AWG applying our proprietary AWG-Parameters tool. The AWG was designed for TM-polarized light with a central wavelength of 850 nm and simulated applying commercial photonic tool PHASAR from Optiwave. The achieved transmission characteristics were evaluated by AWG-Analyser tool....
Article
Full-text available
Photonic Integrated Circuits allow to meet the increasing demand of communication systems for internet which is growing at about 40% per year. This growth is driven mainly by increasing video traffic in the internet network. This growth is now further accelerated by mobile access, with video clients shipping on all smart phones and tablets, enablin...
Article
Full-text available
Hybrid organic–inorganic integrated photonics integrate the organic material, as a part of active layer, with inorganic structure, and it is the organic component that extends the functionalities as compared to inorganic photonics. This paper presents the results of fabrication and characterization of inorganic and organic layers, as well as of hyb...
Conference Paper
Polymeric slot waveguide for photonics sensing was designed, simulated and studied in this work. The polymeric slot waveguide was designed on commercial Ormocer polymer platform and operates at visible 632.8 nm wavelength. Designed polymeric slot waveguide detects the refractive index change of the ambient material by evanescent field label-free te...
Conference Paper
We present the design and simulation of low loss 1x64 Y-branch optical splitter having the symmetric splitting ratio and small footprint. This was reached by optimizing the used waveguide structure that eliminates the presence of the first mode, causing the asymmetric splitting ratio of the split power over all the output waveguides. This way we we...
Conference Paper
We report design and investigation of PECVD SiO2:N/SiO2 slab waveguide grating with a width modulation for sensing application at 1550 nm spectral range. The fundamental parameters of reflected spectrum by grating is simulated and investigated as a function of temperature, cover refractive index and strain. The apodization of designed slab waveguid...
Conference Paper
Photonics is one of the most important technologies of the 21st century. It is the fundament of today's optical communications, all-optical signal processing, biomedical diagnostics, optical sensing, display systems and energy efficient smart lighting. Photonic sensors as a basic part of many photonic systems are under huge development. It is repre...
Article
Full-text available
Abstract. We present the design, simulation, evaluation, and technological verification of various low-index optical demultiplexers based on arrayed waveguide gratings (AWGs). When designing such optical demultiplexers, a set of input geometrical parameters must be first calculated. They are essential to create AWG layout that will be then simulate...
Article
We report on a design and simulation of silicon on insulator apodized surface diffraction grating fiber to chip coupler by sub-wavelength structure which is compatible with 193 nm laser DUV lithography. The structure of designed fiber to chip coupler consists of two parts: a relatively large tapered segment and a segment with the surface diffractio...
Article
Material properties are described by some physical parameters such as temperature or pressure. Optical properties of materials are very important for applications where is light as electromagnetic wave dominant. Behavior of the light in interaction with materials depends on refractive indices. These indices are same for various sizes of materials,...
Article
Colloids compound of Au/Ag nanoparticles with heterogeneous arrangement of two metals were fabricated by various techniques in the past. Laser ablation was reported as a proper technique to fabricate core/shell nanoparticles by Han et al (Appl. Phys. Lett. 92, 023116/1-023116/3 (2008)) and Chen et al (Plasmonics 7, 509-513 (2012)). The detail analy...
Conference Paper
We report on a design for integrated surface diffraction grating fiber to chip coupler designed on Silicon-on-insulator platform with subwavelength grating, which is compatible with 193 nm laser DUV lithography. Surface diffraction grating couplers are perspective coupling solution, which extracts light from the Silicon-on-insulator wire waveguide...
Conference Paper
New approach for reducing of the dimensions of Y-branch optical power splitter by using a two-dimensional photonic crystal (PhC) is reported in this paper. Two-dimensional photonic crystal with photonic band gap was designed and simulated by plane wave expansion algorithm (PWE). This optical power splitter was designed for 1.31 μm wavelength range...
Conference Paper
We present the design, simulation and evaluation of low-index 8-channel, 100 GHz optical demultiplexer based on arrayed waveguide gratings (AWG). The AWG structure was designed using AWG-Parameters tool and the layout was created and simulated using three commercial photonic tools: Optiwave, Apollo Photonics and R-Soft. The design was also technolo...
Conference Paper
In this paper, investigation of the fibre to chip coupler designed on SOI platform with subwavelength grating is reported. This fibre to chip coupler was designed on SOI platform with subwavelength grating, which is compatible with DUV lithography and single step etching fabrication process, for effective refractive index tuning and matching to sil...
Article
Full-text available
In this paper we report on the experimental test set-up for the temperature characterization of optical multiplexers/demultiplexers in the C - telecommunication band. Particularly the temperature change of transmission parameters like polarization dependent loss and insertion loss are investigated. The measurements were performed in the temperature...
Article
With the invention of first laser before 50 years has been proved generation of intense, focused and narrow light beam of one wavelength, also at the same time were fulfilled assumptions for creation memories on light base - Optical Data Storages. Contemporary dynamic memories operate on base electrical impulses, manufactured as matrix arranged MOS...
Article
In the paper, topical problems of photonics education such as the extension of micro/nano-electronics curricula are analyzed. The concept of using optical processes to perform various functions is known as optoelectronics, electro-optics or photonics, and represents a new area for the future. Photonics harnessing the potential of light across a bro...
Article
We have prepared, characterized and discussed the performance of AlGaAs/GaAs heterojunction bipolar phototransistor (HPT) including Zn delta-doped base. Due to the existence of δ-doped sheets located in the middle of undoped GaAs base the δ-doped HPT devices exhibit low dark current, nearly zero offset voltage, saturation voltage ∼0.4 V, and rise a...
Conference Paper
Linear and nonlinear properties of multicomponent glass double core photonic crystal fiber were studied using two samples drawn from the same preform with overall diameter 70 μm and 105 μm. Both dispersion and coupling characteristics of the samples were calculated providing information for observed effective supercontinuum generation at pumping in...
Article
We have fabricated and characterized a resonant cavity enhanced (RCE) optoelectronic devices based on AlGaAs/GaAs and GaAs/InAs material system by various optic and spectroscopic methods. This includes spectral and L-I characteristics combined with near/far-field patterns and optical power analysis. The devices with 45μm diameter top contact connec...
Conference Paper
This paper presents results of numerical simulation of multi-access interference in 2D wavelength-hopping time-spreading optical code division system with bipolar-bipolar codewords. Numerical simulation is based on published numerical model which allows simulating encoder output and decoders input and output signals. Functionality, performance, ver...
Conference Paper
In this work, we demonstrate 2D wavelength-time encoding and decoding OCDMA system. The 2D generalized multi-wavelength prime codewords are used for realization of communication system properties analysis. The encoders and correlators are designed and realized according to used codewords. The experimental data transmission is realized for 80 km opt...
Chapter
Full-text available
We present the modification of decoder for 2-D Wavelength/Time (W/T) Optical Code Division Multiple Access (O-CDMA) system by optical hard-limiters. The performance improvement of the system using proposed decoder modification is shown by numerical simulation of the average Signal to interference difference and Bit error probability as a function o...
Article
The aim of this work is to point on the electrical and optical properties of interdigital MSM photodetectors containing Si delta-doped In0.22Ga0.78As/GaAs QW in dependence of different QW depth under UD GaAs cap layer. For this purposes the delta-doped structure was bevelled. The I-V characteristics in dark and under illumination as well as time re...
Conference Paper
The proposed numerical model of published wavelength-hopping time-spreading optical code division multiple access system with bipolar codewords is presented in this paper. The software was done according to proposed numerical model, which allows simulating encoder output and decoder input and output signal. The verification of correlation propertie...
Article
The proposed numerical model of 2D W/T optical CDMA system with optical hard-limiters is presented in this paper. The decoder input and output signal, average signal to interference difference and bit error probability as a function of active user number and weight of codeword for the different topologies of the decoder have been simulated. The inf...
Article
In this paper we present the proposed modification of 2-D wavelength/time (WIT) decoder1 by placing the second optical hard-limiter (0-HL) after decoder"s last optical coupler. The MA1 improvement of the 2-D W/T Optical Code Division Multiple Access (0-CDMA) system for the cases of 2D WIT decoder with one and with two 0-HLs is analyzed. Average val...
Conference Paper
We present the modification of a decoder for 2D wavelength/time (W/T) optical code division multiple access (O-CDMA) system by optical hard-limiters. The performance improvement of the system using the proposed decoder modification is shown by numerical simulation of the bit error probability as a function of active user number and weight of codewo...
Article
We present the comparison of optical properties of semiconductor stripe lasers including monolayer InAs/GaAs short period superlattice active layers with and without vertical resonant cavity, respectively. The differences between the performances of the conventional laser with vertical cavity indicate a positive influence of the microcavity on th...
Article
Full-text available
We present a structure of an edge-emitting laser with an InAs monolayer active region embedded in an AlAs/AlGaAs vertical resonant cavity. Typical features of these devices are rounded L-I characteristics and a pronounced mode structure in the spontaneous emission spectra. A narrow laser line with a FWHM of 0.17 nm, a lower threshold current densit...
Conference Paper
We present the modification of decoder for 2-D Wavelength/Time (W/T) Optical Code Division Multiple Access (O-CDMA) system by optical hard-limiters. The performance improvement of the system using proposed decoder modification is shown by numerical simulation of the average Signal to interference difference and Bit error probability as a function o...
Article
We present the proposed modification of decoder for 2-D Wavelength/Time (W/T) Optical Code Division Multiple Access (O-CDMA) system by optical hard-limiters. The performance improvement of the system using proposed decoder modification is shown by numerical simulation of the decoder output signal, average signal to interference difference and bit e...
Article
Performance analysis of an incoherent time spread on–off keying optical Code Division Multiple Access (O-CDMA) system with non-ideal optical hard-limiters is reported in this paper. For the first time we made an approximation of the properties of an implemented passive optical hard-limiter. It was named as a non-ideal optical hard-limiter and its n...
Conference Paper
In this work the influence of one and two (Si) δ-doped GaAs layers on the electrical and optical properties of MSM photodetectors has been studied. The sheet concentration and position of δ-doped layers in the structure were confirmed from C-V and Hall measurements. The properties of TiPtAu and TiPdAu Schottky contacts of MSM structures were analyz...
Conference Paper
Speed of response of InGaAs(P)/InP based photodiodes has been analysed with structure parameters and as a function of bias voltage. It is shown that there exists a strong dependence of response time on the valence band discontinuities at the heterointerface InGaAs(P)/InP in the SAM photodiode structure (pile-up effect). The graded InGaAsP layer bet...

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