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Background The revolutionary technology of smartphone-based retinal imaging has been consistently improving over the years. Smartphone-based retinal image acquisition devices are designed to be portable, and easy to use, besides being low-cost which enables eye care to be more widely accessible especially in geographically remote areas. This enables early disease detection for those who are in low- and middle- income population or just in general has very limited access to eye care. This study investigates the limitation of smartphone compatibility of existing smartphone-based retinal image acquisition devices. Additionally, this study aims to propose a universal adapter that is usable with an existing smartphone-based retinal image acquisition device, the PanOptic ophthalmoscope. This study also aims to simulate the reliability, validity, and performance overall of improved develop prototype. Existing studies have shown that the concept of smartphone-based retinal imaging is still limited to screening purposes only. Furthermore, existing smartphone-based devices also have a limited smartphone compatibility where it is only usable with specific smartphone models. Methods A literature review was conducted that identifies the limitation of smartphone compatibility among existing smartphone-based retinal image acquisition devices. Designing and modelling of proposed adapter was performed using the software AutoCAD 3D. For proposed performance evaluation, finite element analysis (FEA) in the software Autodesk Inventor and 5-point scale method were applied. Results It was identified how a universal adapter is beneficial in broadening the usability of existing smartphone-based retinal image acquisition devices as most of the devices that are available in the market have limited smartphone compatibility. A functional universal adapter was developed and found to be suitable with two smartphones that have different camera placement and dimensions. The proposed performance evaluation method was able to generate efficient stress analysis of the proposed adapter design. Conclusion The concept of a universal and suitable adapter for retinal imaging using the PanOptic ophthalmoscope was presented in this paper. Performance evaluation methods proposed were identified to be sufficient to analyze the behavior of proposed adapter when an external load is applied and determine its suitability with the PanOptic ophthalmoscope.

The distributed optical sensors using the multi-input light sources have been designed and simulated. It consists of 6 sensor nodes coupled to the main ring resonator, which is an optical circulator operation. It is a micro-scale device that can be fabricated by the current technology. The three distance light sources are simultaneously fed and the cross-connected signals combined in the circulator. By using the suitable parameters, the whispering gallery modes (WGMs) are generated at the center nodes from which the channel spacing signals can be obtained and used for distributed sensors. The analytical details and the simulation using the selected parameters are presented. The channel spacing of the cross-connected outputs of 1.2 µm is achieved. The simultaneous sensor sensitivity in the terms of ( Δ λ / λ ) of approximately 1.28 is obtained.

We propose a new concept of the nonlinear effect called the Kerr-Vernier effect by using cascaded Si-ChG microring circuits. The circuit is simulated for two materials of different refractive indices which results in phase difference in propagating light and hence observed in the output signal. By varying the input power into the system, the Vernier effects in terms of the Kerr-Vernier effects are seen. In application, the comparative results of the two-channel outputs are used to form the phase sensors, while the self-calibration between the two-channel outputs can be performed. The change in wavelength at the whispering gallery mode of 8 nm is achieved when the applied input power was fixed at 10 mW. A sensitivity of ∼120 µm W-1 is obtained for this proposed sensor.

In this paper, a mesh Ad Hoc network of error-resilient video transmission allows evaluating two disjoint nodes from source to destination. The main drawback of this paper is that it is impossible to safeguard video transmission over reliable channels. An error-resilient video transmission method is utilized over a wide variety of network application needs by using a new method called error diffusion block truncation coding (EDBTC). It is used to remove index color video features creates two-color quantizers and bitmap video. The performance metrics provide both transmissions of videos and non-corresponding disjoint paths to enhance the quality of error concealment video decoder by using proposed EDBTC delivers better video encoder and decoder process than the existing system.

Recently, new advances and emerging technologies in healthcare and medicine have been growing rapidly, allowing for automatic disease diagnosis. Healthcare technology advances entail monitoring devices and processing signals. Advanced signal processing and analytical techniques were effectively implemented in numerous research domains. Thus, adopting such methods for biomedical signal processing is an essential study field. The signal processing techniques are explicitly applied to heart sound (called phonocardiogram or PCG) signals as part of biomedical signals for heart health monitoring in this paper. The automatic detection of life-threatening cardiac arrhythmias has been a subject of interest for many decades. However, the computer-based PCG segmentation and classification methods are still not an end-to-end task; the process involves several tasks and challenges to overcome. The conducted evaluation scheme of the classifier also has a significant impact on the reliability of the proposed method. Our main contributions are twofold. First, we provided a systematic overview of various methods that can be employed in real applications for heart sound abnormalities. Second, we indicated potential future research opportunities. PCG segmentation is critical, and arguably the hardest stage in PCG processing. Basically, basic heart sounds can be identified by detecting the offset R-peak and T-wave in the ECG signal. Unfortunately, utilizing the ECG signal as a reference to the PCG segment is not always an easy operation because: it requires synchronous recording of ECG and PCG signals; precise identification of T-wave offset is often difficult; and ECG-PCG temporal alignment is not always consistent. Using machine learning methods in PCG segmentation involves multiple types and many features retrieved in both univariate or multivariate formats. This leads to selecting the best PCG-segmentation performance feature sets. PCG segmentation approaches that use featureless methods based on powerful statistical models have the potential to solve the problem of feature extraction and minimize the total computational cost of the segmentation approach.

Considering the recent rapid advancements in digital technology, electroencephalogram (EEG) signal is a potential candidate for a robust human biometric authentication system. In this paper the focus of investigation is the use of brain activity as a new modality for identification. Univariate model biometrics such as speech, heart sound and electrocardiogram (ECG) require high-resolution computer system with special devices. The heart sound is obtained by placing the digital stethoscope on the chest, the ECG signals at the hands or chest of the client and speaks into a microphone for speaker recognition. It is challenging task when adapting these technologies to human beings. This paper proposed a series of tasks in a single paradigm rather than having users perform several tasks one by one. The advantage of using brain electrical activity as suggested in this work is its uniqueness; the recorded brain response cannot be duplicated, and a person’s identity is therefore unlikely to be forged or stolen. The disadvantage of applying univariate is that the process only includes correlation in time precedence of a signal, while the correlation between regions is ignored. The inter-regional could not be assessed directly from univariate models. The alternative to this problem is the generalization of univariate model to multivariate modeling, hypothesized that the inter-regional correlations could give additional information to discriminate between brain conditions where the models or methods can measure the synchronization between coupling regions and the coherency among them on brain biometrics. The key issue is to handle the single task paradigm proposed in this paper with multivariate signal EEG classification using Multivariate Autoregressive (MVAR) rather than univariate model. The brain biometric systems obtained a significant result of 95.33% for dynamic Vector autoregressive (VAR) time series and 94.59% for Partial Directed Coherence (PDC) and Coherence (COH) frequency domain features.

The cortical pyramidal neurons in the cerebral cortex, which are positioned perpendicularly to the brain’s surface, are assumed to be the primary source of the electroencephalogram (EEG) reading. The EEG reading generated by the brainstem in response to auditory impulses is known as the Auditory Brainstem Response (ABR). The identification of wave V in ABR is now regarded as the most efficient method for audiology testing. The ABR signal is modest in amplitude and is lost in the background noise. The traditional approach of retrieving the underlying wave V, which employs an averaging methodology, necessitates more attempts. This results in a protracted length of screening time, which causes the subject discomfort. For the detection of wave V, this paper uses Kalman filtering and Cyclic Shift Tree Denoising (CSTD). In state space form, we applied Markov process modeling of ABR dynamics. The Kalman filter, which is optimum in the mean-square sense, is used to estimate the clean ABRs. To save time and effort, discrete wavelet transform (DWT) coefficients are employed as features instead of filtering the raw ABR signal. The results show that even with a smaller number of epochs, the wave is still visible and the morphology of the ABR signal is preserved.

In this paper, the conventional iterative method is applied to study the nonlinear response of light within the chalcogenide glass (As2Se3) resonating system. The proposed system consisted of two cascaded modified add–drop resonators, which is known as a Panda-ring resonator. The feedback circuit is constructed by the two Panda-ring resonators, where the 1st Panda-ring forms the signal system, while the second one forms the feedback system. By using the scattering matrix method, the relationship between the electrical fields in the system is obtained. Four categories of soliton and plane wave input light sources are applied and fed into the feedback circuit, and the nonlinear response of the system is investigated. The various cases of applications are simulated and the results discussed, primarily, for bifurcation applications.

In this paper, the ultra‐wideband source for light fidelity (LiFi) and high‐density 3D imaging applications is proposed. The system consists of an add‐drop multiplexer. The center ring is formed by the Chalcogenide glass (ChG), which is coupled with two GaAsInP/P side rings. The nonlinear effect within the side rings (phase modulators) is induced in the central ring. The superposition of light signals from side rings generates wider wavelength band, which makes the original input. The output is the set of squeezed light pulses known as whispering gallery mode (WGM) which is generated at the center of the system. Three different input sources are investigated, where the simulated results are comparatively plotted and discussed. The results show that the wavelength of 1.30 μm is the best input source. The output wavelengths band is ranged from 0.7‐3.1 μm, which is suitable for LiFi source and high‐density 3D imaging applications.

© 2018 The Authors We propose a new variant of electro-optic multiplexing scheme using the boxcar filter arrangement. The circuits consist of multistage add-drop multiplexers that can offer external input-output connections. Input from a single light source can be fed into the system through the input port or through the free-space from light fidelity (LiFi) node. The light signal is fed into boxcar filters and the roll-off bands are obtained. The output of the circuits is formed at the drop, through and the whispering gallery mode (WGM) node of the circuit output. By using the electro-optic conversion in Si-Graphene-Au layer stack, time division (TDM), wavelength division (WDM), frequency division multiplexing (FDM) can be performed. The simulations have shown that a combination of 7 roll-off bands with the maximum spectral widths or bandwidths of ∼6.09 µm or ∼7.63 THz can be obtained.

An on-chip-scale, up-down link conversion circuit for electro-optic signals to use in a light fidelity network application is proposed. A system consisting of a loop microring resonator (known as a Panda-ring resonator), is coupled inline to the input of a Mach–Zehnder interferometer (MZI). When the light from that source is input into the system, a fraction of the power is coupled inline through successive pumping and then circulated within the system. By using the most appropriate device parameters, the whispering gallery mode (WGM) of the light, with the inline successive pumping condition, is generated at the resonance condition. The transmitted signals are a combination of the comb and WGM signals and are obtained at the MZI output. The simulation results obtained have shown that a maximum power of 300 mW is achieved from the device. A comb signal, over the spectral band from 1.350–1.750 µm is obtained, with the center wavelength at 1.55 µm. The results show an up-downlink switching speed of is ~ 20 fs is also obtained.

We have proposed the use of a soliton pulse that propagates within a modified add-drop filter, which is made of a GaAsInP/P material. It is in the form of a Panda-ring resonator, from which a bright/dark soliton pulse is input into a system via an input port. The conversion between bright and dark soliton pulses is introduced at the 3 dB coupler, i.e. the change in phase of π/2. But it is not superimposed each other. The output solitons obtained at the through and drop ports are bight and dark solitons respectively. Both signals can be used to form “ON’ and “OFF” or “1” and “0”, which are useful for the digital bit generation. The switching speed of the system can be improved by employing the two nonlinear side rings. In application, secure output bits can be arranged by using the alternative input solitons or the control ports, where the input bright and dark solitons can be converted into output bits. This means that the output bits can be randomly switched between “1” and “0”, which can be identified by the sender. Moreover, the additional information can be multiplexed via the add port and transmitted in either free space or optical fiber via the whispering gallery mode and through port outputs. Finally, the electro-optic switching can be transferred and the electronic switching by the embedded stacked layers, where the ultrafast switching of light input can lead the ultrafast electrical switching speed. The switching speed of ~ 5 fs and the offset time of ~ 220 fs of the “on” and OFF” are achieved by using the selected ring parameters.

The electro-optic power pumping system model using the inline successive technique within the modified add-drop filter is proposed. A pumping system consists of a closed loop Panda ring resonator, from which the optical power is coupled inline into the system. By controlling the two side phase modulators, the whispering gallery mode (WGM) is generated by the amplitude-squeezed light within the modified add-drop filter. By using the proposed circuits, the low current can be applied into the system via a gold layer connection, from which the amplified output current can be obtained at the throughput port, which can be functioned as the electronic operational amplifier (op-amp). In application, the WGM output is the amplified signal that can be used for the up (down) link in free space communication network called light fidelity (LiFi). The electro-optic signals conversion can be performed by the stacked layers of silicon–graphene–gold materials. The results obtained have shown that large gain is obtained at the WGM output, which is ~ 5 × $$10^{ - 6}\; {\text{cm}}^{2} \;({\text{V}}\;{\text{sW}})^{ - 1}$$ , when the pumping saturation time is ~ 2 fs. It concludes the suitability of our proposed model for light fidelity, LiFi up-down link conversion.

This study presents the modelling, simulation, and characterization of the Fiber Bragg grating (FBG) on maximum reflectivity, bandwidth, the effect of applied strain to the wavelength shift, ʎB and sensitivity of the wavelength shift with strain for optical sensing system. In this study, a commercial FBG with the center wavelength of 1550nm is used in order to measure the spectral response of FBG to strain. The parameters used in these simulations are the fiber grating length, L ranging from 1 to 10mm, the changes in refractive index, ∆n from 0.0002 to 0.0020, the effective refractive index, is 1.46 and the grating period of FBG,Λ for 530nm in the performance of FBG. The bandwidth and spectrum reflectivity are analyzed from the variation of refractive index and grating length. Simulations on the FBG are carried out using OriginPro 2016 and Microsoft Excel 2010 software. The Excel sheet is used to generate data and the OriginPro 2016 is used to generate the graphs. The results obtained indicates the variation in grating length and refractive index affect the spectral reflectivity and the bandwidth. In addition, results obtained show that the changes in the Bragg wavelength are due to an increase in length of the grating region which due to the applied strain.

We have proposed the convincing electro-optic circuit for long life-time electron mobility emission. Light a monochromatic source is utilized as input into the circuit via the input port and trapped within the plasmonic island. It is a formed-like capacitor structure formed by the silicon-graphene-gold materials which are stacked layers. All circuit port ends have added the TiO2 to form the reflectors. By selecting the suitable parameters, the fraction of the output power emission can be controlled at the add port, from which it can be successively pumping and trapped(stored) within the plasmonic island. The system energy saturation can be released by squeezing light behavior, therefore, the system is always balanced due to the successive pumping process. The results obtained of the single cell(circuit) have shown that the charging time and discharging times of the nano-capacitor-like of ∼2 to 3 s and 1000 h are achieved. This can be applied to long life mobility emission(discharge) of the capacity-like device. The mobility storage time within the island is 14,000 h, with the electron mobility of ∼3.0 × 10−7 cm2 Vs−1 is obtained.

In this paper, a micro-stereo sensor is proposed using two-identical Panda-ring resonators, which are coupled by jointed drop ports. When light from the identical coherent sources is fed into the system via the input ports, the coupling outputs are obtained at the drop port at the resonant condition. These are mixed signals in the form of stereo signals. By using different input power between the right and left systems, the phase difference generated by the Kerr-Effect in the non-linear medium leads to the shift in the coupling outputs. The shift in the center wavelength is the primary measurement of interest along with coupling crosstalk signals that are also visible at the output. The measurement self-calibration of the two channels is confirmed by the mixed channel signals. In the manipulation, the crosstalk signals can be used to interpret the cross-communication of bio-cells. The crosstalk results have shown the optical crosstalks of ∼2.0 and ∼2.5 dB are calculated and obtained, respectively. The stereo sensor sensitivity of ∼5.70 nmW−1is noted.

The temperature sensor using all-pass microrin resonator (APMRR) investigated theoretically and analyzed. An optical bright soliton is used as a probe to study the effect of applied temperature on the light behavior pass through microring waveguide. The split-step Fourier method is used to study the pulse propagation inside the APMRR. Result shows that the rise of temperature on peak amplitude ratio fit with quadratic line in temperature range of 27 oC-37 oC. . The temperature at 30 oC generate higher slope of reduction compare to temperature at 36oC. The amplitude ratio is reduced into 0.6 (-4.4370 dB) when the temperature increased as small as 1 oC. The operating range for all-pass resonator is 97 oC with amplitude reduction of -8.3975 dB.

A microring resonator (MRRs) system incorporated with a add/drop filter is proposed in which ultra-short single, multi-temporal, and spatial optical soliton pulses are simulated and used to kill abnormal cells, tumors, and cancer. Chaotic signals are generated by a bright soliton pulse within a nonlinear MRRs system. Gold nanoparticles and ultra-short femtosecond/picosecond laser pulses' interaction holds great interest in laser nanomedicine. By using appropriate soliton input power and MRRs parameters, desired spatial and temporal signals can be generated over the spectrum. Results show that short temporal and spatial solitons pulse with FWHM = 712 fs and FWHM = 17.5 pm could be generated. The add/drop filter system is used to generate the high-capacity, ultra-short soliton pulses in the range of nanometer/second and picometer/second.

Muhammad Arif Jalil1, Nathaporn Suwanpayak2,3, Kathawut Kulsirirat3, Saisudawan Suttirak3, Jalil Ali4, Preecha P Yupapin31Ibnu Sina Institute of Fundamental Science Studies, Nanotechnology Research Alliance, Universiti Teknologi Malaysia, Johor Bahru, Malaysia; 2King Mongkut's Institute of Technology Ladkrabang, Chumphon Campus, Chumphon, Thailand; 3Nanoscale Science and Engineering Research Alliance, Advanced Research Center for Photonics, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand; 4Institute of Advanced Photonics Science, Nanotechnology Research Alliance, Universiti Teknologi Malaysia, Johor Bahru, MalaysiaBackground: A novel nanomicro syringe system was proposed for drug storage and delivery using a PANDA ring resonator and atomic buffer. A PANDA ring is a modified optical add/drop filter, named after the well known Chinese bear. In principle, the molecule/drug is trapped by the force generated by different combinations of gradient fields and scattering photons within the PANDA ring. A nanomicro needle system can be formed by optical vortices in the liquid core waveguide which can be embedded on a chip, and can be used for long-term treatment. By using intense optical vortices, the required genes/molecules can be trapped and transported dynamically to the intended destinations via the nanomicro syringe, which is available for drug delivery to target tissues, in particular tumors. The advantage of the proposed system is that by confining the treatment area, the effect can be decreased. The use of different optical vortices for therapeutic efficiency is also discussed.Keywords: nanomicro syringe, nanomicro needle, molecular therapy, therapeutic efficiency, cancer

We have experimentally designed a practical pass-through type FBG temperature sensor. The objective of this study is to design and built a prototype outdoor fibre Bragg grating (FBG) temperature sensor system. Its performance is evaluated at different times of the day. In order to reduce the optical losses of the FBG system, the shortest optical fiber path used to connect the FBG system is 55.5m. It has a total connector loss 4.0 dB and fibre loss of 0.3 dB thus giving a total loss of the system as 4.3 dB. The FBG sensor system is connected to the tunable laser source (TLS) and optical spectrum analyzer (OSA). The TLS is used to provide a broadband light source via a fibre optic cable of wavelength 1550 nm. The OSA is used to display the transmission and reflection spectrum to give the Bragg wavelength _B, bandwidth and power dip. The output spectrum can be obtained through direct connection to the FBG. Result of transmission and reflection spectrum show the sensitivity which is calculated from the slope of the graph. The FBG temperature sensor system has an average sensitivity of 9.1 pm (°C)-1 based on the transmission spectrum. It has an average sensitivity of 10.6 pm (°C)-1 based on the reflection spectrum.

A system of dark soliton array (DSA) for secured optical communication using the multiplexed dark soliton pulses is presented. Different wavelength of input soliton pulses with relevant parameters are fed into the rings system while the radii of the rings are 7 μm, 5 μm and Rd = 50 μm. Result shows that the free spectrum range of dark soliton input with the center wavelength of 1503 nm is 0.073 nm. DSA can be obtained using a series of micro ring resonators with input optical solitons of different wavelength, range from λ = 1513 nm to λ = 1517 nm. The DSA can be tuned and amplified used for many application in optical communication such as security purposes. In transmission link, the long distance link of the multi variable network can be performed using DSA.

In this study we propose an interesting system in which a bright and dark soliton pulse can be stopped within a nonlinear nanowaveguide. The system consists of micro and nano ring resonators, in which soliton pulse is input into the system and stopped pulse can be achieved within the nonlinear waveguide. A soliton input is chopped by the nonlinear effects into smaller pulses (chaos). The required pulse is filtered and amplified, which can be controlled and localized within the nonlinear waveguide. The localized bright and dark solitons are stopped by controlling the input power, which means that the photons stopping is controlled by light.

A novel system of dark soliton array (DSA) for secured communication generated by using the multiplexed dark soliton pulses is proposed. The multi soliton pulses with relevant parameters are input into the micro ring resonators system with the radii of 10μm and 5μm. The dynamic dark solitons can be controlled and generated. The DSA are obtained by using a series micro ring resonators with parameters where in the wavelength range of _1 is 15016nm, _2 is 1518nm and _3 is 1520nm. For security applications, the DSA can be tuned and amplified. Thus, the use of DSA for high capacity transmission can be realized by using proposed secured system. In transmission, the long distance link of the multi variable network can be performed by this DSA.

We present a new concept of ASK-to-PSK generation based on nonlinear microring resonators coupled to one MZI arm by using OptiWave FDTD method. By microring resonator increase from one to three microring (SR to TR), we found that the amplitude shift keying (ASK) are increase exactly and the phase shift keying (PSK) is equal to π.

A novel design of molecular buffer for molecule storage and delivery using a PANDA ring resonator is proposed. The optical vortices can be generated and controlled to form the trapping tools in the same way as the optical tweezers. In theory, the trapping force is formed by the combination between the gradient field and scattering photons, which is reviewed. By using the intense optical vortices generated within the PANDA ring resonator, the required molecules can be trapped and moved (transported) dynamically within the wavelength router or network, in which the molecular buffer can be performed within the wavelength router before reaching the required destination. The advantage of the proposed system is that a transmitter and receiver can be formed within the same system, which is available for molecule storage and transportation. Relevant patents are also reviewed in this manuscript.

Light has found applications in data transmission, such as optical fibers and waveguides and in optoelectronics. It consists of a series of electromagnetic waves, with particle behavior. Photonics involves the proper use of light as a tool for the benefit of humans. It is derived from the root word “photon”, which connotes the tiniest entity of light analogous to an electron in electricity. Photonics have a broad range of scientific and technological applications that are practically limitless and include medical diagnostics, organic synthesis, communications, as well as fusion energy. This will enhance the quality of life in many areas such as communications and information technology, advanced manufacturing, defense, health, medicine, and energy. The signal transmission methods used in wireless photonic systems are digital baseband and RoF (Radio-over-Fiber) optical communication. Microwave photonics is considered to be one of the emerging research fields. The mid infrared (mid-IR) spectroscopy offers a principal means for biological structure analysis as well as nonintrusive measurements. There is a lower loss in the propagations involving waveguides. Waveguides have simple structures and are cost-efficient in comparison with optical fibers. These are important components due to their compactness, low profile, and many advantages over conventional metallic waveguides. Among the waveguides, optofluidic waveguides have been found to provide a very powerful foundation for building optofluidic sensors. These can be used to fabricate the biosensors based on fluorescence. In an optical fiber, the evanescent field excitation is employed to sense the environmental refractive index changes. Optical fibers as waveguides can be used as sensors to measure strain, temperature, pressure, displacements, vibrations, and other quantities by modifying a fiber. For some application areas, however, fiber-optic sensors are increasingly recognized as a technology with very interesting possibilities. In this review, we present the most common and recent applications of the optical fiber-based sensors. These kinds of sensors can be fabricated by a modification of the waveguide structures to enhance the evanescent field; therefore, direct interactions of the measurand with electromagnetic waves can be performed. In this research, the most recent applications of photonics components are studied and discussed.

We propose a novel system of a quantum-molecular transportation using the multi-optical tweezers, whereby the transportation of molecules in the communication system can be performed. Initially, the generated transporter can be formed by a dark soliton. It can be tuned and attenuated to a single photon by bright soliton control and transmitted into an optical link. The molecule transportation states can be identified by using a single photon state of the transporter, which can be formed in the transmission line. The proposed device can be fabricated using InGaAsP/InP, and can provide the required output signals. The design system consists of a nonlinear microring/nanoring resonator system incorporating an add/drop filter and a quantum signal processor. In applications, the proposed system incorporating a quantum processor can perform secure molecular communication as part of a molecular communication based data network.