SiON is a suitable material for the implementation of photonic integrated circuits with a middle refractive index contrast
for the visible and near infrared region. The paper presents the design, fabrication and characterization of SiON/SiO2/Si
structures for passive optical waveguides realization with designed refractive index contrast 0.13. This refractive index
contrast allows fabrication of strip SiOx/SiON/SiO2/Si waveguides with waveguide band losses bellow 0.01dB/cm at
150um waveguide radius. SiON and SiOx layers were fabricated by plasma-enhanced chemical vapor deposition
techniques. The plasma-enhanced chemical vapor deposition technological parameters were tuned and optimized
for designed refractive index contrast 0.13 and designed waveguide thickness 2.5 m. The refractive index of fabricated
SiON layers were measured by optical ellipsometry.
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 techniques. The motivation for the reported work was to design a low-cost polymeric slot waveguide for sensing arms of integrated Mach-Zehnder interferometer optical sensor with reduced temperature dependency. The minimal dimensions of advanced sensing slot waveguide structure were designed for researcher direct laser writing fabrication by nonlinear two-photon polymerization. The normalized effective refractive index changes of TE and TM fundamental modes in polymeric slot waveguide and slab waveguides were compared. The sensitivity of the normalized effective refractive index changes of TE and TM fundamental modes on refractive index changes of the ambient material was investigated by glucose-water solutions.
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 simulated using commercial photonics tools. However, these tools do not support or support only partially such a fundamental calculation. Therefore, a new stand-alone tool called AWG-Parameters was developed, which strongly reduces the time needed for the design. From the calculated geometrical parameters, the AWG layouts were created and simulated using three commercial photonic tools: Optiwave, (Ottawa, Ontario, Canada), Apollo Photonics, (Ancaster, Ontario, Canada), and R-Soft, (Pasadena, California). The designs were also technologically verified. The simulated/measured transmission characteristics were evaluated by our newly developed AWG-Analyzer tool. This tool provides calculations of AWG transmission parameters, which are also missing in commercial photonic tools. Additionally, the tool provides clear definitions of calculated transmission parameters together with their textual and graphical representations. Finally, the transmission characteristics and parameters achieved from different photonic tools were compared with each other and discussed in detail. The simulated results were also compared with the measurements. Very good agreement was achieved between theoretical (AWG-Parameters tool), simulated (commercial photonic tools), and fabricated AWG transmission parameters.
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, but in
nanoscale dimensions, they depend on some phenomena. Herein, we present the study of the silver (Ag) nanoparticle
(NP) monolayer film and its dielectric properties. The aim of the study is to explain phenomenon why it is necessary to
use effective material properties for Ag NPs, where these properties are size-dependent. The plasmonic properties of NP
have been investigated by the finite domain time difference (FDTD) simulation methods. Although the good agreement
of plasmonic resonances was found for gold (Au) NP film, a significant mismatch in the resonance energy for Ag NP
film was observed. The deviation was assigned to the presence of silver oxide (Ag<sub>2</sub>O) in Ag NPs as a surface layer. This
real structure of Ag NPs can be replaced by structure with suitable effective material properties. Results depict
importance of the effective material properties in Ag NP film for reason of the presence of silver oxide. The Ag NPs with
surface oxide exhibits linear tendency in the deviation of the effective dielectric function, which agrees with the
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 diffraction grating
having sub-wavelength structure. The first segment adjusts cross-section of silicon on insulator wire single mode
waveguide to standard single mode fiber diameter and the second one is designed for vertical coupling to the fiber. Four
types of surface diffraction grating apodization by sub-wavelength structure are designed and simulated. The simulation
of the fiber-to-chip coupler is performed by FDTD simulation method. The simulation results of coupling effects for
each apodization of surface diffraction grating are evaluated and compared with each other.
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 analysis
of plasmonic properties for several metal arrangements has been done using the finite-difference time-domain (FDTD)
method. The nanoparticles have been modeled as (i) core/shell nanospheres, (ii) bimetallic particles consisting of two
parts (Au and Ag), or (iii) colloid consisting of pure Au and Ag nanoparticles. Results of numerical simulations show
that all three investigated nanoparticle metal arrangement systems exhibit shift of the plasmonic wavelength with
increase of the Ag/Au volume ratio in a similar way as recorded in the experiment. It points out that it is not possible to
distinguish the metal arrangements in nanoparticles by the optical methods only and the conclusions from optical
properties can be misleading. Thus optical methods can certainly prove only that bimetallic nanoparticles consist of alloy
or phase separated metals.
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 and emits it towards an optical fiber placed over the SOI chip<sup>1</sup>. However, they are polarization and spectral sensitive. Efficient grating-to-fiber coupling requires matching the grating radiated field profile and the optical fiber mode. The aim of this design is the reducing back reflection of the fiber to chip coupler by using subwavelength grating for continuously tuning effective refractive index and tune the profile of diffracted power. The structure of designed fiber to chip coupler consists of relatively large tapered segment which adjusts cross-section of SOI wire waveguide to standard single mode fiber diameter and surface diffraction grating for vertical coupling to the fiber. The simulation of the fiber to chip coupler is performed by FDTD tool and BPM tool. The effective refractive index is tuned over diffraction grating by adjusting the duty cycle of the silicon in subwavelength grating inside the surface diffraction grating.
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 and it is based on AlxGax-1As/GaAs material platform. Optical power splitter was designed by RSoft's Photonic
Component Design Suite and 3D simulations were performed by beam propagation method (BPM). The PhC
implementation with suitable pattern in to Y-branch optical power splitter leads to spread the optical signal on it.
It results in sharper division and it is way how to decrease dimensions of optical power splitter. Position of PhC in
structure of optical power splitter can change splitting ratio.
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
MOSFET transistors with capacitors, and reach time delay (latency time) in ones nanoseconds. Transfer data rates are
above ones of Gbps. Current storages are approaching technologically threshold parameters, what may be barrier to
further development, whereas Optical Data storages multiple exceed transfer data rates of contemporary memories, not
require reverse O/E/O signal transformation, operate in pico-seconds (ps) and work at low energetic levels of femto-
Joules. New end-user services lay still bigger emphasis for transferred and stored data volumes, transfer rates, quality of
transmission and data processing, whereby they partly pushing out contemporary storages and create place for optical
memory elements used in telecommunication networks and in devices. Optical storages with their several-fold higherdensity,
high transmission rates, better quality and small dimensions are becoming a new trend for dynamic buffer or
balancing memories, used for long-term data archiving in plasmonic nano-structures within Holographic Data storages.
In this paper we present the proposed modification of 2-D wavelength/time (WIT) decoder<sup>1</sup> 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 value of signal-to-interference difference (SID) is used as the MA1 merit. The model of such 2D W/T
0-CDMA system for numerical calculation of the SID is proposed and presented in this paper. In the analyzed system,
2-D WIT Generalized Multiwavelength Prime Codewords (GMWPC), which are generated by algorithm reported in<sup>2</sup> are
used for achieving multiple-access. We assume the implemented 0-HL proposed in <sup>3</sup>. The properties of such 0-HL were
approximated  and its two ideality parameters, which characterize the measure of its ideality, were defined. The input
and output time optical pulses sequence of W/T 0-CDMA decoder is numerical simulated. Dependencies of SID versus
the weight of codeword and the number of active users in the system are presented. The influence of the properties used
0-HLs is evaluated.
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 influence of non-ideal properties of the used optical hard-limiters and different topologies of the decoder upon average signal to interference difference and bit error probability in system are studied.