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A transparent, flexible graphene field effect transistor (GFET) based on ferroelectric gate is demonstrated. In this device, the single layer graphene was fabricated by chemical vapor deposition method, and transferred to the polyethylene terephthalate substrate. Then the poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) ferroelectric polymer layer film was used as the gate dielectric for the graphene FET. Based on the P(VDF-TrFE)/graphene heterojunction FET, Hall Bar structure was fabricated. The transport properties of the graphene channel at low temperature and retention characteristics at different temperature are investigated in detail. These special properties indicated that the GFET might be useful for many particular applications, such as a non-volatile memories, flexible electronic devices and phototransistors.

The spatial self-phase modulation effect in graphene oxide with silver and gold nanoparticles were considered for demonstration of nonlinear properties of nanocomposites. Gold and silver nanoparticles were fabricated in graphene oxide using laser ablation at different times. The prepared samples were characterized using UV–Visible, transmission electron microscopy and X-ray diffraction spectroscopy. The absorption peaks in blue and green ranges were appeared related to silver and gold nanoparticles, and the nanoparticles were capped by graphene oxide in a spherical shape. The concentration of nanoparticles increased with an increased the ablation time. The nonlinear effect in graphene oxide and graphene oxide with gold and silver nanoparticles was then observed using the spatial self-phase modulation technique at 532 and 405 nm wavelength. Consequently, the self-defocusing effect was appeared in the mentioned medium, and the number of spatial self-phase modulation rings increased with an increased volume fraction of nanoparticles.

The graphene and graphene oxide sheets were prepared from directly exfoliated and Hummer’s method. Nitrogen doping was applied with the assistance of ultra-sonicator to achieve doping via a simple, low-cost aqueous route. The size of graphene and graphene oxide sheets was examined by transmission electron microscopy with a size of several micrometer. The doping phenomenon was achieved by the addition of aqua ammonia and the analysis were examined by Raman microscopy. The approve of N-doping was got with the appearance of G′ band. The existence of nitrogen element were further examined by energy dispersive spectroscopy.

The paper describes design and analysis of Tera Hertz Optical Asymmetric Demultiplexer (TOAD) switch using quantum dot semiconductor optical amplifier (QDSOA) and all- optical digital to analog converter (DAC). The QDSOA based TOAD or QDSTOAD and the DAC performance optimization for control power variations shows that 1.5 mW pump or control power gives the optimized performance as far as the extinction ratio is concerned for the TOAD. At the same power absolute error (e) and dynamic range for DAC also shows maximum. The present paper investigates relative output, absolute error and dynamic range for the performance analysis of the DAC. An absolute error as low as 0.25% and dynamic range (11.765 dB) very close to the ideal value (11.761 dB) ensures effectiveness of these devices. These devices show immunity to the amplified spontaneous emission noise.

Reduction in the dimensions of silicon based devices has produced extraordinary developments in the performance of electronic systems. Recently, the advantages and challenges that caused by silicon devices shrinking have been investigated in many studies. Most of them have concluded that silicon technology is coming to an end and new innovations are required in the near future. Graphene is the promising candidate material as building blocks for nanoelectronic industry in order to silicon technology replacement. Graphene is first two dimensional materials that has significant potential in future nanoelectronic devices and other nanotechnology applications; therefore, it is an attractive subject for the researchers and scientists. Graphene is a carbon allotrope and is the basic element of other carbon allotropes. In this paper, main graphene production approaches are mentioned. The mechanical, thermal, optical, electrical, electronic and other fundamental properties of graphene are introduced. Moreover, it is considered as a novel material with numerous applications, which, we mention a few of important utilizations of graphene and its derivatives. Then, the different types of defects in graphene and their specifications, the methods of defect generation, defect healing, and properties of defective graphene are studied. Graphene nanoribbons and their geometric structures, fabrication approaches and electronic specifications are investigated. The effects of width, vacancy defect and doping concentration on the band structure of the graphene nanoribbons are extracted with ATK software in this paper. Simulation results showed that by increasing in the width, vacancy defect and doping concentration of nanoribbons, their band gap were decreased. These properties are suitable for controlling the channel of graphene nanoribbon field effect transistors.

Quantum well infrared detector has been extensively applied in military and civil fields. In order to break through the bottleneck of low quantum efficiency, a novel quantum well infrared photodetector based on SiO2–dielectric–metal microstructure has been proposed and investigated in this paper. The detector is composed of three layers, which are SiO2 particle array on the top, quantum well in the middle layer and metallic film at the bottom. The results shown that the SiO2–dielectric–metal sandwich structure can absorb electromagnetic waves between 14 and 15 µm which the quantum well infrared photodetector work at. In addition, we have studied the influence of the parameters of the detector structure, it is found that the absorption band is insensitive to period of photodetector microstructure and the thickness of SiO2 layer, which indicates the quantum well infrared photodetector has a stable performance. The quantum well infrared detector proposed in this paper has large potential applications in the miniaturization and integration of optoelectronic devices in the future.

Visible Light Communication (VLC), which gives communication alongside illumination, has increased a great deal of enthusiasm amongst researchers. VLC system needs to consider dimming control to offer effective communication while illuminating. In this paper, a dimming control scheme based on pulse position modulaton (PPM) and inverse PPM is proposed, which supports different dimming levels. PPM supports low dimming value whereas inverse-PPM has an inherent property of supporting higher dimming value for the same block length. Hence, the proposed scheme utilizes both PPM and inverse-PPM to achieve different dimming target values. This paper presents the algorithm for encoding and decoding of multi-header hybrid pulse position modulation (MH-HPPM) scheme and also shows the NI Labview SubVI code for generating the MH-HPPM frame under dimming values of 0.25, 0.33, 0.5, 0.67 and 0.75. Simulations are executed in MATLAB 2017a to simulate random input bits using the proposed scheme in the VLC system for different dimming values and evaluate the BER performance of the scheme. The simulation result shows that the proposed scheme performs better for dimming value $$\alpha = 0.25$$ , block length $$K = 4$$ , is bandwidth efficient and hence can be considered as an alternate dimming control scheme.

This paper introduces a fractal model of the Radhakrishnan–Kundu–Lakshmanan (RKL) occurring in a fascinating physical phenomenon in birefringent fibers. He's variational approach is used to identify novel fractal RKL-equation optical soliton solutions. The required novel criteria to ensure the existence of appropriate solitons are provided. The three-dimensional surfaces of the recording solutions are demonstrated by specifying a variety of suitable parameter values. The focus of this paper is on the groundbreaking RKL-equation work frontiers and other associated nonlinear evolution models in the field of optical solitons and solitary waves.

In the complex background of information warfare, we often encounter multiple air defense radars or multi-band radars and carry out effective jamming against them simultaneously. Due to that radar always works at different frequencies, we need to generate jamming signals with sufficient bandwidth, covering all frequencies of radar and aiming at each band at the same time for jamming, which is called multi-point targeting jamming. In this paper, using two coherent optical frequency combs through the Vernier caliper effect with frequency “dislocation” is proposed, and produce multiple stable central frequencies through beat frequency. This scheme can realize widely tunable frequency bands. And this paper implemented maximum tunable range of 1.1–23.4 GHz with 100 MHz bandwidth.

Improvement of visible light communication (VLC) technology and the presence of the illumination encouraged the researches to research in VLC-based indoor positioning. Recently, researchers published several papers on VLC based localization systems, however there are not a lot of survey papers in this issue. In this paper, a deep analysis survey of VLC based localization systems is introduced. Researches from pioneering papers to the state-of-the-art in the field of VLC based position are analyzed and classified based on the localization techniques, types of transmitters and receivers, and multiplexing techniques. Different from other surveys, we analyze the accuracy of VLC based localization system in the practical and simulation environments.

This paper studies bright highly dispersive optical solitons that are with nonlocal type of nonlinearity. The numerical scheme, adopted in the paper, is Laplace-Adomian method. The analytical results, reported earlier, and the numerical results from the current work, agree with an impressively small error measure.

The dispersion of optical fiber can damage optical information, thus limiting data transfer speed and transmission distances. In this paper, a new structure is presented by applying metal nanoparticles for photonic crystal fibers (PCF) so that minimizes dispersion and optical loss. The proposed PCF uses circular and elliptical shape nanoparticles, then their number and location is optimized by PSO algorithm. Applying metal nanoparticles in PCF substrate causes increases the conductivity and increases light excitation, which increases light absorption and decreasing dispersion. By changing the shape, location, and type of nanoparticles, a structure with minimal dispersion and light loss is provided. In this paper, we applied three elliptical and three circular nanoparticles using the PSO results. The hexagonal PCF is designed with air grids and radius of 5.8 µm, and then circular and elliptical gold particles are used instead of air holes. Simulation results show that the loss is 7e−4 dB/cm at wavelengths between 1.3 and 1.65 µm and the dispersion is obtained less than 0.3 ps/nm/km. The light loss and dispersion are reduced compared to other related studies.

A MoS2-Graphene hybrid layer Based High Performance Refractive Index SPR Sensor is illustrated in this paper. Intended for the enhancement of sensor angular sensitivity (S), signal to noise ratio (SNR), quality factor (QF), first of all, the impact of gold layer thickness is investigated and optimized to 40 nm, after then the MoS2 and graphene coting layers are optimized to four (4) and three (3) layers, respectively. Further that, at this optimum structure, the minimum reflectance and SPR angle are decorated. It is seen that the angular sensitivity of the optimum assembly, improved to excellent value of 130 deg-RIU−1 with improved angular SNR of 1.37 and QF of 17.02 RIU−1. At the end of this paper, an analysis specifically for numerically DNA hybridization is considered.

Free space optical (FSO) communication system has obtained significant importance in communication field due to its unique features: unlimited spectrum, larger bandwidth and high data rate, low mass and less power requirements, quick and easy deployability. FSO system better suits in disaster recovery, defense and last mile problems in networks, remote sensing and so on. However, FSO system has greater advantage, its performance is mainly degraded by adverse effects like beam wandering and spreading, scattering and mainly a major degradation factor is atmospheric turbulence and pointing errors which leads to severe degradation in Bit error rate (BER) and Signal to noise ratio (SNR) of the FSO link and makes the communication link infeasible. This paper gives a detailed survey on performance enhancement of FSO communication system and also discusses various channel distribution models and modulation techniques to have high reliability and FSO link availability. In this paper, the various atmospheric effects like turbulence, fog, absorption and scintillation and so on are discussed. The first part of the paper analysis the channel models and the latter part of the paper summarizes the different modulation techniques, diversity techniques and also the comparative study of the (SNR) and (BER) under various atmospheric factors of the FSO system. This survey provides the comprehensive details in order to provide low cost and high capacity FSO link design.

Visible light communication (VLC) is a rising guaranteeing new innovation for optical wireless communication with taking part favorable circumstances not available on radio communication. Especially, as connectivity propagation, both across the world and via the Internet of Things. Any communication system is based on the LED light is luminous to verifying the connection. The major challenge in VLC is how to make a communication system to download data in the dark light when indoor lighting is not needed. This paper explains how visible light can be used to transmit data even when the light appears dark or off. We investigate VLC minimum illumination to receive power, to enable users to receive data when the light is “OFF”. This paper focuses on improving the system performance including signal to noise ratio, required power and bit error rate. VLC with different modulation schemes highlighting as the On–OFF Keying, Pulse Position Modulation, L-Pulse Position Modulation, and Inverse L-Pulse Position Modulation are investigated in the dark light for communication. A short part of Pulse Width Modulation is used for dimming illumination. The paper examines the selected parameters and essential requirements of VLC dark light system which are power, bandwidth efficiency and the dimming factor of light sources. We confirm that dark light is enough to keep up information paces of a few kbps. This looks good for the eventual fate of VLC for actualizing shrewd lighting systems.

The large differences between the refractive index of Si and SiO2 in the SOI composite (silicon on insulator) and, as a result, its high ability to trap lasers, have led to the construction of valuable optical equipment in recent years. In this paper, with a new idea, by adding two reciprocating golden walls and a transverse air gap, the SOI structure is developed in such a way that equipment made with the new method, such as XOR and NOT gates and power-phase comparators, have a dreamy speed and a super small size. This structure is only compatible with linear polarization so that the axis of polarization, which is the direction of the electric field, is parallel to the gold plates. In the multifunctional structure presented in this paper, if the inputs are uniform plane waves, the output will be uniform plane wave with high accuracy and that the inputs can be phase or power while the output is only power. Simulation in this paper is done using finite-difference-time-domain method.

The aim of the paper is to see the influence of Franckeite on the sensing application of SPR based biosensor. Franckeite is an emerging (2D) material from sulfosalt family having naturally presented spontaneously vander Waals (vdW) Heterostructure. We have investigated and carried out detailed analysis to design the high-performance biosensor by exploiting the unique properties of Franckeite. The performance of the biosensor is quantified in terms of Sensitivity and other performance parameters. Proposed work is theoretical where we have proposed a surface plasmon resonance (SPR) biosensor in combination of the nanosheets of (Bimetallic layer + Franckeite + TMDC + BP) in order to enhance the sensitivity. It’s also shown in the paper that by sandwiching a buffer (polymer) with low refractive index (close to water) between metal layer (Au in this case) and dielectric medium prism, the value of FWHM reduced dramatically and significant enhancement observed in FOM (100RIU−1) and detection accuracy (2.38 deg−1). We have also illustrated the concept of long range –SPR (LRSPR) in this paper by giving the comparative analysis of different polymers. As an air-stable 2D material, we expect that 2D Franckeite Nano sheets could have potential applications in the field of chemical as well as biosensing application in the future.

The aim of this work is to point out the current possibilities of using polarized light in sensor technology. Furthermore, the aim is to demonstrate the possibility of using the fiber sensor of thermal field disturbance as a truly feasible biomedical sensor applicable in medicine and especially to analyse different ways of measuring polarization changes. This paper concludes theoretical and experimental study deal with temperature response of birefringent fiber. It is supposed to use it for design of sensor of temperature disturbance. The paper follows up on the previous works, where the response of the birefringent PANDA fiber to thermal exposure in the temperature range from 0 to 48 °C was studied. These experiments analyzed the dynamic sensitivity characteristic of birefringent fiber for the process of thermal source apposition. The present paper brings a detailed comparative analysis of fiber response to the processes of apposition and the removal of thermal source, which are evaluated from the point of view of the system’s response after the ending of the thermal exposure. For practical use in fiber recovery analyses, the phase development rotation senses are described on the observable Poincare sphere.

In this paper, a novel topology for refractive index optical fiber sensors based on surface plasmon resonance (SPR) phenomenon is presented. The fiber core has a graded refractive index and there is a hole at the center of the core which is coated by silver. The analyte is injected into the hole. In our structure, there is no need for removing the cladding of the fiber. Two types of graded refractive index profiles are investigated in this paper. The proposed sensor is simulated using finite difference time domain method. The results show that the presented SPR sensor has a good spectral response and suitable sensory specifications. The sensitivity of the proposed sensor is about 4350 nm/RIU. The figure of merit of this sensor is 149 RIU−1. The proposed sensor can be used for measuring refractive indices between 1.38 and 1.49. As a result, it can be used for bio-sensing applications. One of the advantages of the proposed sensor is that it is label-free.

In this paper, the perturbed nonlinear Schrodinger equation with dual-power law of nonlinearity is studied by adopting four mathematical methods namely the Modified Kudryashov method, the extended Tanh–Coth method, the modified simple equation method and soliton ansatz method. As a results, a set of various types of solitons that contains dark, singular, dark–singular, bright optical solitons and other form of optical soliton solutions are obtained. Firstly, we solve the perturbed nonlinear Schrodinger equation by considering the dual power law parameter using the first three integration methods and secondly we set this parameter equal to one in order, to solve the problem with the fourth method. The used methods in this paper present various applications in fields of nonlinear wave equations. Comparing our new results with well-known in literature are also given. Moreover, the graphical representations of the modulus of some optical soliton solutions and their 2-D profile are also depicted.

In this paper, a hybrid technique using a precoder and a µ law compander is proposed to alleviate light emitting diode (LED) nonlinearity as well as peak-to-average power ratio (PAPR) reduction in a VLC system. A µ law compander is used to compress the peak valued signal and enhances small amplitudes to lower the PAPR. The work attains optimal PAPR and improves bit error rate (BER) of the system at low signal to noise ratio values. The nonlinear characteristic of a LED used as the transmitter in a VLC system leads to damaging effects while using OFDM in an optical system. The combination scheme improves LED nonlinearity for low input back off (IBO) power. In the work, nonlinearity is characterized using error vector magnitude (EVM) in percentage. The proposed method shows a 5% EVM improvement for 0 dB IBO. The paper provides a choice for a trade-off among PAPR reduction, BER and reduced nonlinearity.

In this paper, we propose a new design of plasmonic organic solar cells (OSCs). It consists of a protective layer of SiO2, an anti-reflective glass of ITO, a compact buffer of PEDOT:PSS, an absorbing organic material of P3HT:PCBM, and a reflective layer of Al. A square periodic array of core–shell nanoparticles (Au@ITO NPs) is embedded in the active layer of P3HT:PCBM in order to enhance the absorption of OSC. Although ITO coating slightly reduces efficiency, it prevents the oxidation of gold NPs and increases the OSC lifetime. We study the effect of numerous parameters such as the core radius, shell thickness, and core material on the optical absorption by solving Maxwell’s equations using the three-dimensional finite-difference time-domain method. The drift–diffusion and Poisson’s equations are solved with an in-house software tool by discretizing the solar cell using the finite element method. To the best of our knowledge, this paper is the first to apply the real model of trap-assisted recombination and Auger recombination of used materials to the simulations to match them with the experimental results. The numerical results show the proposed OSC embedded with Au@ITO NPs has the built-in potential of 2.9 V, short-circuit current of 16.63 mA/cm2, the open-circuit voltage of 1.14 V, maximum power of 17.25 mW/cm2, fill-factor of 0.91, the conduction band of 2.8 eV, electron quasi-Fermi level of 2.35 eV, hole quasi-Fermi level of 0.6 eV and an efficiency of 17.25%. Furthermore, the performance of the proposed OSC has an improvement of 25% compared to conventional OSCs.

The optical response to the linear and circular polarized light of the double-spirals structures are investigated by the finite element simulation in this paper. For the linear polarized light the double-spirals structures are like a linear polarizer in the long wavelength region with the wavelength of 900–1500 nm, which corresponds to the standing-wave mode of a single spiral. The double-spirals structures have evident chiral effect in the long wavelength, and has 3–4 circular dichroism (CD) peaks in the wavelength range 850–1500 nm. For all structures investigated in this paper, the CD spectra have obvious blue shift with the increase of the arm width. The simulation results also indicate that the smaller the distance between the two spirals, the more the chiral effect of the double-spirals structures. The chiral effect for both structures with the distance of 400 nm diminishes, and both structures no longer have typical CD spectra.

In this paper, an optical absorber based is exploited on self-similar cylindrical for material detection in the infrared spectrum as a refractive index sensor. Two models are suggested and the effect of the gaps is discussed. Actually, the gaps can be used for intensifying the absorption and improving the figure of merit (FOM). The absorber is modified for 300 THz (1000 nm) with reflection value of − 45 dB (0.004) which is made this absorber as a good choice for optical refractive sensing. This study shows the importance of the parasitic elements and gaps for improving the sensing quality and FOM value. In fact, the reflection of the Nanoabsorber is increased extremely without using the parasitic element up to − 14 dB. As shown in this paper, the FOM of the prototype absorber is enhanced more than 10 times for some refractive indexes by implementing of gaps. The maximum value of the FOM is 400 RIU−1 for the final model with gap and the maximum sensitivity is 204 nm/RIU obtained for the structure without the gap. In brief, these gaps can be considered for increasing the FOM more than the basic model.

High sensitivity and rapid detecting photonic sensors are essential devices such as in medical diagnostics and biological test. Conventional biochemical sensors based on the directional couplers need other apparatus to measure the precise output power intensities. Conversely, a digital sensor is more efficiently utilized to determine the refractive index of the liquid sample. By simple mathematics induction, the formulae of designing a general photonic digital sensor, which comprises k (k ≥ 1) levels of the directional couplers composed of the ridge waveguides, are obtained in this paper. The performance of the sensor resembles an analog-to-digital converter and distinguishes 2k liquid samples. As long as k is large enough, the sensor can lower the quantization error and precisely determine the refractive index of the liquid sample. To demonstrate the validity of our formulae and design rules, we present the beam propagation method simulation results in this paper.

Free space optical (FSO) communication has gained significant attention among researchers for high bandwidth and secured data transfer applications. However, its performance is limited by the local atmospheric conditions. This paper focusses on an FSO system employing a diversity method to compensate signal loss occurred due to atmospheric turbulence conditions varying from moderate to strong. We derive a closed-form expression for two important parameters, viz.: average bit error rate (BER) and outage probability over gamma–gamma distribution channel. The numerical results for different combining schemes are presented in this paper. Enhancement in reliability and performance of FSO communication system with wavelength diversity is investigated. Effect of different wavelengths 850 nm, 1310 nm and 1550 nm on average BER is analysed and minimum BER is achieved for optimal combining at 1550 nm at diversity order $$R=3$$ .

Implementation of high-speed switching activity in the all-optical domain is one of the required necessities for modern high-speed technology and secured communication. The paper includes the interesting method describing micro-ring resonator structures as switching logic, exploring it to implement the active low tri-state buffer in the all-optical domain structures. The paper shows the switching activity of micro-ring resonator structures along with the corresponding graphs are discussed, including what happens when enabling the effective active high/low all optical tri-state buffer logic functionality. The application and advantage of tri-state buffer logic in the all-optical domain are explained.

The enterprising of nematicons has procured considerable recognition during the last few years due to its utilization in crystal technology. This research work contains some new exact traveling waves solutions in nematic liquid crystals. The modified simple equation method is employed to extract new traveling wave solutions. Two types of nonlinear mediums are investigated in this paper. New singular, periodic-singular and spatial solitons in liquid crystal are obtained by using analytical approach. The constraints fall out as the byproduct that guarantee their existence. The solutions are also highlighted graphically. This paper is leading to explore some unaccustomed results into this area of research.

This paper deals with exact soliton solutions of the nonlinear long–short wave interaction system, utilizing two analytical methods. The system of coupled long–short wave interaction equations is investigated with the help of two analytical methods, namely, the generalized $$\tan (\phi /2)$$ -expansion method and He’s semi-inverse variational method. Moreover, in this paper we generalize two aforementioned methods which give new soliton wave solutions. As a consequence, solutions are including solitons, kink, periodic and rational solutions. Moreover, dark, bright and singular solition solutions of the coupled long–short wave interaction equations have been found. All solutions have been verified back into its corresponding equation with the aid of maple package program. We depicted the physical explanation of the extracted solutions with the free choice of the different parameters by plotting some 3D and 2D illustrations. Finally, we believe that the executed methods are robust and efficient than other methods and the obtained solutions in this paper can help us to understand the soliton waves in the fields of physics and mechanics.

Under investigation in this paper is a nonlinear conformable time-fractional Boussinesq equations as an important class of fractional differential equations in mathematical physics. The extended trial equation method, the $$\exp (-\Omega (\eta ))$$ -expansion method and the $$\tan (\phi (\eta )/2)$$ -expansion method are used in examining the analytical solution of the nonlinear fractional equations. The proposed methods are based on the integration method and a wave transformation. The fractional derivative in the sense of conformable time-fractional derivative is defined. Fractional complex transform is implemented to change fractional differential equations into ordinary differential equations in this paper. In addition, explicit new exact solutions are derived in different form such as dark solitons, bright solitons, solitary wave, periodic solitary wave, rational function, and elliptic function solutions of nonlinear conformable time-fractional Boussinesq equations.

This paper introduces basic concept of the detection range of a low-light-level (LLL) imaging system, and on the basis of previous derivation of visual distance detection equation for the LLL imaging system, the influence of noise factor on visual distance of LLL night vision system is discussed emphatically. Image intensifier is the most important part of LLL night vision device and SNR is one of the important parameters of micro-light image intensifier, whose value determines the detection distance and image sharpness of LLL imaging system in low-light conditions. In this paper, using system noise factor relation, by modifying the noise factor, a more practical and perfect horizon detecting equation is established, and the horizon estimation is carried out with the experiment, and the practicability of the corrected Horizon formula is verified. It has a certain guiding significance for improvement of the LLL imaging system and the development of night vision technology.

Glass frit encapsulation for laser-base sealing of the complex interiors results challenges for the electronics manufacturing process. The conventional frit packaging method relies on elevating thermal process by furnace where the package is heated to required temperature, hence limiting the use of temperature-sensitive materials and also creating problems in different packaging processes or multi-stage sealing products. In this paper, the benefits of combining novel laser-assist hermetical sealing and low temperature glass frit packaging are demonstrated and the technique offers a suitable and feasible solution. This frit of absorbent at specific laser wavelength is selected and applied as excellent contact with both large CTE range substrates. Glass frit composites consisting of a PbTiO3 ceramic and the rare earth Nd2O3 are evaluated for thermal properties and electrical characteristics. This developed glass frit hermetical sealing method achieves moisture durability, satisfying the enculturation of electronics-level. In this paper, we demonstrate successfully using laser to seal organic light emitting diode (OLED) via low melting temperature glass frit.

In the field of the optical computing, all optical logical functionality possesses the central importance. The descriptive paper puts some interesting phenomena associated with micro-ring resonator (MRR) switching activity. The different types of logic functionality can be implemented using the MRR structures. There are some considerable advantages, e.g. compact size, immunity to electro-magnetic interference, low attenuation, higher bandwidth and safe computing. The paper includes the detailed mathematical description about the all optical 4 bit binary to gray code converter. The proposed scheme is verified using the MATLAB simulation result.

The paper presents a novel all-optical two bit asynchronous up counter using integrated 2D square lattice photonic crystals. The design of optical counter relies on optical SR flip flops are designed using the photonic crystals (PhC). The total size of the proposed optical counter is equal to 90 μm × 40 μm, and the structure has lattice constant ‘a’ is equal to 630 nm and band gap range from 0.32 to 0.44. The PhC structure has a square lattice of silicon rod with refractive index of 3.39 in air with permittivity of e = 10.1 × 10−11 F/m. The structure is simple, which make it suitable for all optical integrated circuit. Besides, the paper provides analytical and numerical simulation on the overall system using the dimensional finite difference time domain and plane wave expansion methods to confirm its operation and feasibility.

An InAlAs/InGaAs/InAs quantum dots–quantum well in double barrier structure was simulated and analyzed in this paper. InGaAs electroluminescence spectrum, photoluminescence spectrum and current–voltage are numerically investigated in detail. Further, the photocurrent spectrum of the detector based on quantum dot in well with near-infrared response and the response can be tailored to 1.70 μm. The S (signal)/N (noise) may work on 3.5 and −1.3 V at 300 K. The paper also presents the observation of photo memory under different external driving voltage and the storage time can reach about 80 μs by a light pulse. At last, the oscillation is observed by a low temperature test for the GaAs/AlAs hybrid structure, which is attributed to a sequential single-phonon emission by ballistic electrons.

The modulation enhancement performance of inkjet-printed random coding metal particles lattice is studied in this paper. By optimizing duty ratio of metal particles lattice, the modulation depth of optical-controlled terahertz wave modulators can reach to 62 and 83 % with periodic configuration and random coding structure, respectively. Their optimized modulation depths are nearly 1.3 times and 1.7 times of reference device, respectively. The random coding device has better performance mainly because the random distribution lattice leads more incident pumping light to be absorbed by substrate material due to the multiple scattering. Besides, the influence of different solvent heating treatments on modulation depth is also studied in this paper. The heating treatment with hotplate has more opportunity to form high quality metal particles and greatly improves the performance of modulator. Our study not only provides an alternative route to develop high performance optical-controlled terahertz wave modulators, but also brings an alternative way to other research area such as terahertz antenna, solar cell, etc.

In this paper, the characteristics of the transmission coefficient (S$$_{21}$$ 21 ) measured in free-space at terahertz frequencies are analyzed. The analysis results are used to estimate the permittivity of the material under test, and the estimated permittivity is adopted as an initial-value for the iterative algorithm to extract the complex permittivity of the material from the S$$_{21}$$ 21 . The iterative extraction technique based on the estimation is efficient, while the iterative extraction technique without the estimation is inefficient. Various known materials in the literature are used to validate the technique in the terahertz band.

The application of nanoparticles in the transparent displays due to the unique properties of nanoparticles is one of the best and most efficient methods. The considering of two-dimensional Gaussian distribution for nanoparticles both radius and position is also common because of its natural and physical properties. In this paper, we intend to achieve the optimal structure for transparent display by the Gaussian array and changing some parameters such as distance between nanoparticles, the radius of nanoparticles, etc. Therefore, we can obtain the maximum scattering cross-section and the maximum scattering to absorption ratio (SAR) with an optimally designed structure. In these structures, we use spherical Si/SiO2 nanoparticles at blue, green, and red wavelengths. By achieving a narrower peak for scattering cross-section and a higher amount of SAR, we can increase the amount of contrast and transparency for transparent monochrome and transparent color displays.

Reducing the dark current of InGaAs/InP avalanche photodiodes (APDs) is an important way to improve its performance. Decreasing the active size can reduce the dark current but sacrifice the quantum efficiency. In this paper, the metal–insulator-metal (MIM) microcavity is integrated with an APD, which can converge light from tens of micrometers to several micrometers, so as to compensate for the loss of detection efficiency caused by the reduction of the size of the APD. Through photoelectric joint simulation, the optical response of the device can be obtained, and the coupling effect between the MIM structure and the APD can be analyzed directly. The simulation results show that the photocurrent to the dark current ratio of the APD integrated with the MIM microcavity is twice of the MIM free traditional APD, and the 3 dB bandwidth reaches 5.8 GHz. When the MIM microcavity is applied to an APD array, the optical crosstalk between pixels is found to be negligible.

In this paper, two novel electro-optical decoders based on graphene-dielectric-metal waveguides are proposed for use in the infrared region. The use of graphene instead of noble metals improves the efficiency of the device due to higher confinement, lower losses, and the capability of controlling the propagation of light via electrostatic doping. Simulation results demonstrate that the minimum extinction ratio is more than 36 dB for the proposed 2 × 4 decoder. The footprint of this decoder is 8 μm2 which represents an ultra-compact structure. By following the design rules, a 3 × 8 decoder with a minimum extinction ratio of 23 dB and a footprint of 29 μm2 is presented. Also, the proposed structure can act as a simultaneous half-adder/subtractor circuit by applying some changes. The Sum and Carry bits have extinction ratios of 24.66 dB and 28.2 dB, respectively. The half-subtractor part of the circuit calculates two X–Y and Y–X subtraction operations simultaneously. The minimum extinction ratios of Difference and Borrow bits are 22.39 dB and 25.98 dB, respectively. Also, the footprint of the half-adder/subtractor circuit is less than 33 μm2.

Generally, for gas imaging, narrowing the response of the camera sensor around the target gas’s absorption band would increase the imaging contrast. In this paper, A filter-free narrowband metallic cavity quantum well infrared photodetector is proposed. The metallic cavity is formed by Ti/Au film coating on the detector’s mesa. The geometry of the cavity is properly designed to sustain cavity mode resonating at 10.6 μm. With strong resonance, the absorption efficiency of the embedded quantum well active layer maintains high level (~ 74%) even with a fairly low doping concentration (~ 1 × 1017 cm−3). And the bandwidth is as narrow as 0.22 μm. A waveguide model is presented and used to analyze the metal cavity quantum well infrared photodetector, and it is found that the metal film coating on the side wall played an important role in enhancing the resonance and narrowing the spectral line width.

The exploration of noise performance for a laser system is one of the most charming topics in optics community. Photo-receivers designed to be stable, low-noise, and high-dynamic-range for a specified laser device are of vital significance to the noise characterization systems. In this paper, principle criteria for customizing photo-receivers used in amplitude- and phase-noise measurements of mode-locked laser systems were presented, and real examples were given for a 100-MHz repetition-rate Ti:Sapphire mode-locked laser. High-dynamic-range output voltage noise spectral density of 5.2 nV/√Hz and 35.6 nV/√Hz for amplitude- and phase-noise photo-receiver, and stability of 70.8° phase margin at loop-gain closure point up to 207 MHz for phase-noise photo-receiver were implemented.

Due to atmospheric turbulence, the wavefront phase and the light intensity distribution would change, and the information carried by beams may be damaged or even lost. Hence, using the non-Kolmogorov spectrum and the generalized Huygens-Fresnel principle, the propagation characteristics of circular-linear edge dislocation beams are studied in this paper. The results show that the light intensity distribution of the beams eventually evolves into the light intensity distribution of Gaussian-like beams. Circular edge dislocation and linear edge dislocation evolve into two pairs of optical vortices. When the beams propagate far enough, two pairs of optical vortices will annihilate. With the decrease of the inner scale of turbulence and the general exponent, and the increase of the general structure constant, the evolution of the beams will be accelerated. The effect of the outer scale of turbulence on the evolution can be negligible. The results obtained provide theoretical guidance for optical communications and spatial modulation of optical fields.

The application range of hyperspectral imaging is subject to the operational system platform especially relies on the core imaging spectrometer. With a rising practical requirement of extensive remote sensing recently, the traditional method of two or multiple separate imaging submodules combined has obviously brought inevitable shortages in certain cases such as mineral detection or environmental monitoring, etc. Not only is the whole imaging system somewhat so large in physical size and so high in weight that it has an objective influence on convenience as well as flexibility in actual operation, but also each independent instrument has unique optical parameters and assembling matrices after fabrication and alignment which is against the image consistency. Instead of common image correction and data processing, the essential solution is to set up a broadband integrative system platform. This paper introduces a new prototype of imaging spectrometer in the visible and near-infrared (VNIR) to short-wave infrared (SWIR) region. Different from most existing research-based and commercial VNIR to SWIR imaging spectrometers, it is designed as broadband integration of a single core module. The main optical system consists of a collimating mirror, a central dispersive spherical prism, a converging mirror and two plane mirrors on the sides, which is similar to the normal convex grating spectrometer of three-concentric-mirror (Offner) configuration. The imaging spectrometer has relatively high imaging quality and satisfactory instantaneous field of view (IFOV) with a fairly compact internal structure benefiting from the integrated design and conscientious fabrication. The approach not only avoids extra expense and alignment complexities of multiple spectrometers but also enhances radiometric stability and reduces stray light and polarization effects. Relative performance tests are performed in various specific environment and validating imaging experiments are represented on schedule to demonstrate the expectant effectiveness of the whole system.

With the widespread of the Internet and the rapid growth of technologies, several challenges face data hiding process. Although watermarking is widely used to hide/embed critical data into a cover image, the watermarked image may be attacked/hacked and the embedded data may be extracted or damaged. This paper presents an efficient two-level security approach to protect colored watermark images. In the first level, the color image is embedded into a grayscale image using a multi-level Discrete Wavelet Transform (DWT), Singular Value Decomposition (SVD), and wavelet fusion. In the second level, an additional encryption process on the watermarked image is done by using two-dimensional logistic chaotic map in a case and Advanced Encryption Standard (AES) in another case. The proposed scheme is evaluated by using several images and different hacks on the transmitted image. The experimental results show that the proposed scheme is efficient and can face many attacks such as Gaussian, Blur, Wrap, and Cropping. In addition, the extracted watermarks are recognized even when the marked images suffered from attacks.

This paper retrieves a spectrum of soliton solutions propagating through magneto-optic waveguides that maintain a wide range of nonlinear refractive index structures. The implemented algorithm is the extended version of $$G^{\prime }/G$$ –expansion scheme. The existence criteria for such solitons are also presented.

In this work, we presented a radio-over-fiber (ROF) access network through two modulation stages for the generation of multiple millimeter wave (mm-wave) signals with frequencies of 20GHz, 40GHz, 60GHz and 80 GHz for the transmission rate of 10 Gbps as a function of the variation of link distance and signal power. The specific purpose of the paper was to design and to investigate a RoF system based on the variation of mm-wave frequencies in order to implement a simple and effective system. In stage 1, there are two modulators in parallel (MZMa and MZMb) called dual-parallel Mach-Zehnder modulator (DP-MZM) and in stage 2 there is only one modulator (MZMc), connected to three pulse generators: Non-Return-to-Zero (NRZ), Return-to-Zero (RZ). A single-mode fiber (SMF) and Gaussian and an erbium-doped fiber amplifier (EDFA) were also used to send signals to base stations (BSs). The numerical analyzes of the results of the eye diagrams showed excellent bit error rate (BER) and quality factor (Q-factor) values, which proved the good performance of the proposed ROF DP-MZM system, for the three encoding formats used, which was able to generate 3-tupling mm-wave for multiple wireless accesses.

The capacitance of the photodiode still remains some ignored issues. It will facilitate the further analysis and simulation of the capacitance of photodiodes to analyze on the capacitance of the p–i–n InAlAs/InGaAs/InAlAs infrared photodiode. In this paper, the capacitance is divided into two parts, diffusion capacitance and depletion capacitance, to discuss with models in which we solve the divergence of depletion capacitance(CT) at forward bias and take the deep level traps into consideration. Furthermore, we explore the dependence with the delay factor by the calculation of capacitance–voltage (C–V) characteristics. It shows that the delay factor is related to the applied voltage and the frequency.

This paper presents a configurable structure to realize all-optical photonic crystal logic gates based on the interference effects. The photonic crystal waveguides are realized by creating defects in a square lattice of silicon rods in the air. The proposed structure consists of four input ports, including two ports for applying input signals of logic functions and two ports for applying control signals. Therefore, all-optical NOT, OR, XOR, AND, NOR, and NAND logic gates as well as $${\overline{\text{A}}} \cdot {\text{B}}$$ and $${\overline{\text{A}}} + {\text{B}}$$ logic functions can be implemented. Simulations are performed using the finite-difference time-domain method. The simulation results show high extinction ratios (ERs) of logic gates operating in the optical communication C band. The lowest ERmin is related to the NAND logic gate with a value of 14.2 dB at the wavelength of 1.55 μm. The maximum propagation delay is equal to 285 fs, corresponding to the OR and AND logic gates. Also, the total footprint of the structure is about 192 μm2. The presented configurable structure is a promising candidate for use in integrated photonic circuits.

Due to the fabrication processes, inaccurate manufacturing of the photonic crystals (PCs) might occur which affect their performance. In this paper, we examine the effects of tolerance variations of the radii of the rods and the permittivity of the material of the two-dimensional PCs on their performance. The presented stochastic analysis relies on plane wave expansion method and Mote Carlo simulations. We focus on two structures, namely Si-Rods PCs and Air-Holes PCs. Numerical results show—for both structures—that uncertainties in the dimensions of the PCs have higher impact on its photonic gap than do the uncertainties in the permittivity of the Si material. In addition, Air-Holes PCs could be a good candidate with least alteration in the photonic gap considering deviations that might occur in the permittivity of Si due to impurities up to 5%.