Optical Software Research Articles

Contactless Optical Packaging Concept for Laser to Fiber Coupling

A novel method for the laser to fiber coupling is presented in which coarse alignment is achieved through micromachined v-grooves and mirrors in a fused silica substrate. Furthermore, fine repositioning is done in a noncontact manner by using a femtosecond laser to induce localized nanoscopic volume changes in specific locations within the bulk of the substrate, which, once combined with monolithic flexures within the substrate, produces a highly controlled motion. Using this principle, we overcome inherent manufacturing/assembly tolerances to achieve near theoretical coupling efficiency in a permanent manner. This proof of concept demonstrates a novel packaging principle where a sub-nm positioning resolution is achieved over tens of micrometers range of motion, efficiently overcoming intrinsic manufacturing tolerances.

Assessment of plasma power deposition on the ITER ICRH antennas

Ion cyclotron resonance heating (ICRH) is one of the three additional heating schemes to be deployed on ITER. Its two antenna arrays, installed on the outboard midplane, will deliver 20 MW of RF power in the 40–55 MHz frequency range. The plasma-facing component of the antenna assembly is the Faraday screen, comprising beryllium (Be) tile armoured, actively cooled bars located only ~1 cm radially behind the innermost point of the shaped Be first wall panels (FWPs). As such they are in close proximity to the scrape-off layer (SOL) plasma and it is important to assess the maximum heat loads that the screen bars may experience during high power ITER operation. This paper provides a detailed assessment of these loads using the new 3D field line tracing and power deposition framework SMITER (Kos et al., 2019). The focus is on the H-mode, burning plasma scenario, taking into account both plasma heat loading (including average loading due to mitigated Type I ELMs) and the loads due to photonic impact (assessed with the optical ray-tracing package Raysect (Meakins and Carr, 2017)) from power radiated in the core obtained from integrated JINTRAC simulations. Calculations are also performed to assess the minimum allowed antenna to magnetic separatrix distances, for cases in which closer approach may be required to improve RF coupling.

Hybrid photonic system integration using thin glass platform technology

Demand for high integration of optoelectronic and micro-optical components into micro-electronic systems for communication, computing, medical, and sensing applications is increasing. Advanced hybrid packaging technologies are used to enhance glass-based substrates featuring electrical, thermal, and optical functionalities with laser diodes, modulators, isolators, photonic integrated circuits (PIC), beam-splitting components, and micro-lenses. Such glass-based substrates can be thin glass layers on large panels or more mini-bench-like boards that can be embedded into organic printed circuit boards (PCBs). Optical fiber interconnects, connectors, and electrical–optical integration platforms are used for higher level system integration and need to be miniaturized on module and board level to fulfill decreasing channel pitch requirements. We provide background on and discuss thin glass as a suitable base material for ion exchanged waveguide panels and interposers, precise glass structuring for posts and holders, the related high precision assembly techniques, and advanced fiber interconnects. Some examples of PCB photonic integration, micro-bench optical sub-assemblies, including PIC, and 3D optical resonator packages that combine most of these approaches will be shown.

Survey on Medical Imaging of Electrical Impedance Tomography (EIT) by Variable Current Pattern Methods

Recently, the image reconstruction study on EIT plays a vital role in the medical application field for validation and calibration purpose. This research article analyzes the different types of reconstruction algorithms of EIT in medical imaging applications. Besides, it reviews many methods involved in constructing the electrical impedance tomography. The spatial distribution and resolution with different sensitivity has been discussed here. The electrode arrangement of various methods involved in the EIT system is discussed here. This research article comprises of adjacent drive method, cross method, and alternative opposite current direction method based on the voltage driven pattern. The assessment process of biomedical EIT has been discussed and investigated through the impedance imaging of the existent substances. The locality of the electrodes can be calculated and fixed for appropriate methods. More specifically, this research article discusses about the EIT image reconstruction methods and the significance of the alternative opposite current direction approach in the biomedical system. The change in conductivity test is further investigated based on the injection of current flow in the system. It has been established by the use of Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software (EDITORS) software, which is open-source software.

Signal to interference plus noise ratio improvement of a multi‐cell indoor visible light communication system through optimal parameter selection complying lighting constraints

AbstractTo achieve improved communication and illumination performances of a multi‐cell indoor visible light communication system, the selection of transmitter configuration and receiver's field of view (FoV) play a critical role. Based on multiple criteria decision modeling, a design‐centric methodology is proposed in this paper to determine the optimal transmitter configuration and receiver's FoV under lighting constraints. These optimal parameter selections are instrumental to obtain a highly uncorrelated channel, thus significantly mitigate both co‐channel interference from the neighboring transmitter and intersymbol interference due to multipath reflection. The implication for the optimum selection is explored using two communication and two lighting (Eavg, UO) performance indicating metrics. For a typical indoor scenario, three different transmitter arrangements with varying half‐power beam‐width are considered as alternatives. Furthermore, the signal to interference plus noise ratio (SINR) is tested over the communication floor (CF) by a simple receiver structure with a single photodiode. Incorporating the optimal transmitter configuration and receiver's FoV, 36.13 dB average SINR and 345 lx average horizontal illuminance is achieved. Analytically obtained SINR is also validated using a commercial ray tracing optical software for different positions over the CF. In comparison with the state of the art non‐optimal and sub‐optimal solutions, the proposed scheme, without real‐time computational complexity exhibits noteworthy improvement in SINR performance at expense of a trivial drop in overall uniformity of horizontal illuminance.

Optical performance of a multi-faceted microstructure light guide plate based on optical simulation Tracepro software

Optical performance of a multi-faceted microstructure light guide plate based on optical simulation Tracepro software

PENGEMBANGAN MODUL PRAKTIKUM UNTUK PERBANDINGAN UNJUK KERJA SUMBER CAHAYA OPTIK LED DAN LASER DALAM SISTEM KOMUNIKASI OPTIK

LED optical light source and laser diode function as an information carriers in the opticalcommunication systems. Each optical light source in the form of LED, CW Laser, and VCSEL Laserhas advantages and disadvantages. Based on these advantages and disadvantages, a study wascarried out on the internal and external characteristics of optical light sources to determine the optimaloptical light source to use as needed. Simulations are carried out in optical system software. Theperformance analyzed is Q-Factor, BER, and Eye Diagram until it reaches the ITU-T G.984.2standard with a minimum limit of Q-Factor = 6 and BER = 10-9. The feasibility test of the practicummodule uses the method of filling out a questionnaire with a Likert scale of 1–5 and giving pre andpost-test to the practitioner. The results of this study were an increase in the internal characteristics ofthe LED, a decrease in the signal power of the CW Laser, and an increase in the bias current of theVCSEL Laser resulting in a decrease in Q-Factor, and an increase in the BER value. The comparisonof the increase in bit rate and transmission distance showed that CW Laser can transmit a higher bitrate and a longer transmission distance. The comparison of the transmission distance that can becovered by each optical light source shows that the CW Laser travels the farthest transmissiondistance . Increased understanding of the practitioner based on the post-test score which is higherthan the pre-test score can be used as the basis that this practicum module as a whole is verysuitable for use as teaching material. This is also supported by the feasibility test of the questionnairefilling method with a Likert scale of 1-5 with a percentage of the practitioner's assessment of 88.6%.

Computer Modelling of the Optical Behavior of Homogenizers in High-Flux Solar Furnaces

Solar radiation homogenizers are multi-mirror devices that try to reshape the solar radiation distribution coming from a concentrator, so that, after passing through the homogenizer, the light flux becomes as much evenly distributed as possible. The optical behavior of these multi-reflective devices is complex and still ill-understood. The geometry of the concentrator defines the features of the concentrated flux and then the characteristics of a particular homogenizer must be chosen according to the envisaged use. In this work, we developed and used optical ray-tracing software to investigate how the homogenizer’s optical output is affected by the following homogenizer’s characteristics: (i) Number of reflecting surfaces; (ii) total length; (iii) position (relative to focal plane); and (iv) tilt angle (inclination) of reflecting surfaces. The obtained results provide valuable information for the use of these optical devices and may contribute to the development of more efficient strategies for homogenization of concentrated radiation generated by high-flux solar furnaces.

Comparison of Anatomical and Functional Results of Surgeries Performed with Nitinol Flex Loop or Forceps in Primary Epiretinal Membrane

ABSTRACT Purpose: To compare surgery’s effect with nitinol flex loop (NFL) or forceps on retinal layers and functional outcomes in the primary epiretinal membrane (ERM). Methods: The operations were classified according to the use of the NFL or forceps. Automatic segmentation of the individual inner retinal layers was performed by spectral-domain optical coherence tomography software, and best-corrected visual acuity (BCVA) before surgery and at the last follow-up visit postoperatively were compared. Results: Forty-two eyes of 42 patients were included with a mean age of 66.9 ± 5.7 years. 45.2% of the surgeries were NFL assisted, 54.8% were forceps assisted. The mean follow-up duration was 9.8 ± 1.3 months. The mean BCVA was 0.79 ± 0.42 vs 0.77 ± 0.39 logMAR in the preoperative period and 0.42 ± 0.27 vs. 0.40 ± 0.21 logMAR at last follow-up in the NFL vs forceps group respectively (p= .403). The retinal nerve fiber layer (RNFL)(32.5% vs. 50.1%, p= .009), ganglion cell layer (18.1% vs. 41.4%, p= .021), inner plexiform layer (13.5% vs. 32.7%, p= .031) and inner nuclear layer (15.5% vs. 30.3%, p= .011) thickness decreased significantly more in the forceps group. The mean surgical time was not significantly different (45.2 ± 5.1 vs. 51.1 ± 6.1 minutes) in the NFL vs. forceps groups, respectively (p= .331). Conclusion: Following primary ERM surgery, the inner retinal layers become thinner; RNFL impacted the most, which was found higher in forceps assisted surgeries. This result shows that the NFL can be used safely in macular surgery.

Opto-mechanical design and calibration of a hyperspectral irradiance monitor.

A hyperspectral irradiance monitor (HIM) is designed to measure the direct solar spectral irradiance on the ground, which can be used for research on climate change and vicarious calibration. The spectrometer uses a Féry prism to disperse and converge light, and a linear image sensor (NMOS) measures the spectral irradiance ranging from 400 nm to 1100 nm. The instrument utilizes two flat mirrors to fold the optical path, and optical software is used to optimize the key parameters. The dispersion equation of the prism and two characteristic wavelengths of the laser are utilized for the spectral calibration, for which the uncertainty of the spectral calibration is less than 0.8 nm. A standard lamp is used for the spectral irradiance calibration, for which the uncertainty of the spectral irradiance calibration is less than 2.78% (k=2). The instrument runs stably in the field.

Assessment of micro-abrasive wear tribological properties of H10 tool-steel under conditions of “constant normal force ⇒ variable pressure” and “constant pressure ⇒ variable normal force”

In industrial applications, tools of H10 tool-steel used in mechanical and metallurgical manufacturing processes, such as rolling, extrusion, forging, sheet metal stamping, milling and turning, frequently present significant levels of micro-abrasive wear, which occurs under specific circumstances of “constant normal force”, resulting in a “variable pressure” physical condition, or “constant pressure”, resulting in a “variable normal force” physical condition. Consequently, results of micro-abrasive wear generated under these tribological conditions can help engineers design materials and tools with a longer working life span when they are working under mechanical and metallurgical manufacturing processes. Observing the relevance of this subject, the purpose of this work is to assess the micro-abrasive wear tribological properties of H10 tool-steel submitted to experimental conditions of “constant normal force ⇒ variable pressure” or “constant pressure ⇒ variable normal force”. Ball-cratering wear tests were conducted on quenched and tempered AISI H10 tool-steel; the counter-body was a quenched and stress-relieved AISI 52100 bearing steel sphere and the abrasive slurries were prepared mixing abrasive particles of silicon carbide with distilled water. During the micro-abrasive wear tests, the abrasive slurry was, continuously, agitated and fed between the sphere and the tested material; values of coefficient of friction were, simultaneously, acquired, as well. After the tests, each wear crater was analyzed by optical microscopy, SEM and CAD software. The results were discussed based on the behavior of the “Steady-State Wear Regime”, “wear volume”, “wear rate”, “micro-abrasive wear modes”, “pitch between grooves”, “coefficient of friction” and, finally, validated by ANOVA. With the attainment of the Steady-State Wear Regime, it was possible to present the following conclusions: (i) wear volume and wear rate increased under conditions of “constant pressure ⇒ variable normal force”, (ii) there was the predominance of “grooving abrasion”, with the action of “micro-rolling abrasion” wear phenomenon, (iii) the pitch between grooves presented, approximately, the same value of the average abrasive particles size and (iv) the coefficient of friction remained in a tribological condition classified, statistically, as “constant”.

WITHDRAWN: Robokart for visually impaired people

Abstract This paper proposes a system that can be installed on a shopping cart that be used to assist visually impaired people. This method uses the concept of ROI, text localization and recognition by optical character recognition software and a webcam controlled by Raspberry Pi. Two micro controllers are used to program both the shopping cart movement and OCR. The user is required to give a voice input of the required product and the ROBOKART guides the user to that product.

Selected methods for starch content determination in plant materials

This manuscript presents selected analytical methods for starch content determination in plant materials. The presentation includes tools and equipment needed to apply a selected method and method accuracy in determinations of starch content and parameters. An overview of these methods may be useful while designing studies focused on starch content in materials of plant origin. The manuscript also discusses the effect of microwave radiation on selected parameters of starch granules. In addition, it presents results of an experiment aimed at determining the response of potato starch granules to microwave radiation. In that experiment, the size of potato granules was measured using an OPTICA B-510BF optical microscope and PROVIEW x64 software, 3.7.13483.20181206. The results obtained were analyzed at a significance level of α=0.05 using STATISTICA 13.3 software package.

Response of potato starch granules to microwave radiation

This study aimed to determine the response of potato starch granules to microwave radiation indicated by changes in starch granule size. Laboratory analyses were carried out in 2019 with tubers of an early edible potato cultivar Innovator. The tubers were irradiated for 10-600 s using a 100 W generator producing microwaves having a frequency of 2.45 GHz. Dimensions of starch granules were measured using an OPTICA B-510BF optical microscope and PROVIEW x64 software, 3.7.13483.20181206. The results were analyzed in STATISTICA 13.3. software package at a significance level of α=0.05. The microwaves were shown to significantly modify the maximal diameter and surface area of potato starch granules.

A Dielectric Dome Antenna With Reduced Profile and Wide Scanning Capability

The design and experimental validation of a wide scanning dome antenna with reduced profile is presented. The antenna is based on the combination of a planar phased array with limited scanning capabilities and a dielectric lens which allows to broaden the field of view. The angular variation of the scan loss can be almost arbitrarily designed if no constraint is imposed on the size of the dielectric lens. However, the focus of this article is on the size minimization of the dome as required for applications where the form factor is critical. Therefore, a lower boundary of the height of the dome is derived and imposed as a design constraint. The antenna is analyzed using in-house ray tracing and physical optics software tools. It is shown that, when the array is combined with the dielectric dome, a significant directivity enhancement can be achieved for wide scanning. A demonstrator of the lens is designed, manufactured and combined with an available phased array working in Ku-band. The experimental tests confirm the theoretical predictions, validating the analysis tools, and show a scanning range of 70° in all scanning planes over a 15% bandwidth. The directivity is enhanced by approximately 2 dB at the limits of the scanning range compared to the standalone illuminating array. The active element pattern is rotationally symmetric, thus, the radiation performance is almost independent on the scanning plane. Moreover, the dielectric lens allows to preserve the cross-polarization performance of the illuminating array without adding a significant contribution.

Greenhouse cover plate with dimming and temperature control function

A new type of greenhouse cover plate with light and temperature control function is proposed. The optical software is used to simulate the concentrating characteristics of the cover plate. The simulation results show that the new cover plate has the characteristics of higher receiving rate when the incident angle is small, higher transmittance when the incident angle is large, and this tendency is more obvious when the position of fluid channel become higher and the radius become smaller. The experimental samples were processed and the acceptance rate and transmission rate were tested in typical sunny weather. The experimental and simulation results are matched well. At noon, the transmittance of the new cover plate reaches about 35% of the lowest in a day, while that of the double glass cover plate is about 70%. This new type of cover can not only realize the light control function, but also realize the efficient thermal utilization of solar energy, so it has a broad application prospect.

Optimal selection of threshold in EIT reconstructed images for estimating size of objects

It is useful to convert reconstructed images to binary form for quantitatively establishing shapes and sizes of objects. In this work, we present guidelines for selecting appropriate threshold values based on systematic numerical investigations assuming prior knowledge of conductivity contrast. Various configurations of objects immersed in a background were considered. Open source software electrical impedance diffused optical reconstruction software (EIDORS) was used for reconstructing differential EIT images for these configurations. Diametric conductivity profiles were used to identify appropriate values of threshold to obtain accurate object size over a wide range of contrast. The calculated values of threshold and the resulting effect on estimated object size were compared with the usually preferred thresholds of 1/2 (FWHM) and 1/4 (FWQM) of maximum amplitude on the basis of size accuracy. It was found that the proposed threshold offers better size accuracy with respect to change in position and size of the object over a wide range of contrasts. The proposed threshold values were found to work satisfactorily for 15 dB signal to noise ratio and 10% error in conductivity contrast.

基于DMD的小型近红外光谱仪原理及优化分析

The DMD small near-infrared spectroscopy instrument is widely used in chemical composition analysis and quality inspection for its advantages of fast detection speed, high sensitivity, no damage detection, and miniaturization of portable instruments. However, as the premise of instrument design, optical optimization design of the whole spectral range is the hard work of the system. In this paper, the theoretical design method of the spectroscopic imaging system based on the small near-infrared spectrometer of DMD was studied. The method was designed by using the double-dispensing anti-aberration lens and combining the geometric aberration theory to optimize the design of a small DMD near-infrared spectrometer to reduce the aberration of the entire system. Then, the optical simulation software was used to align the direct imaging system for optical simulation. And ultimately achieve the design simulation requirements. Simulation results indicate that the whole size of the spectrometer is less than 150 mm×150 mm×150 mm, and the resolution is better than 15 nm in the range of 1000-1700 nm in the working band. Therefore, the proposed method can meet the design requirements and has broad application prospects in practical applications.

Optical coherence tomography angiography findings in patients with ocular and non-ocular Behcet disease.

To evaluate the optical coherence tomography angiography findings in patients with Behçet disease with and without ocular involvement. A total of 40 patients with Behçet disease and 30 healthy controls were enrolled in the study. Retinal vessel density in the superficial capillary plexus and deep capillary plexus, foveal avascular zone area and perimeter, acirculatory index, foveal density, and nonflow area in the superficial retina were automatically measured using the optical coherence tomography angiography software AngioVue and compared between the groups. The mean parafoveal and perifoveal vessel densities in the superficial capillary plexus and deep capillary plexus and foveal density were significantly lower in the eyes with Behçet uveitis compared to the eyes without Behçet uveitis and eyes of the healthy controls. In the eyes with Behçet uveitis, logMAR visual acuity showed a moderate correlation with parafoveal and perifoveal vessel densities and foveal density (r=-0.43, p=0.006; r=-0.62, p<0.001; r=-0.42, p=0.008; respectively). Behçet disease with posterior uveitis was associated with significant perifoveal and parafoveal vascular decrements in the superficial and deep retina.

Video Capsule Endoscopy and Ingestible Electronics: Emerging Trends in Sensors, Circuits, Materials, Telemetry, Optics, and Rapid Reading Software

Real-time monitoring of the gastrointestinal tract in a safe and comfortable manner is valuable for the diagnosis and therapy of many diseases. Within this realm, our review captures the trends in ingestible capsule systems with a focus on hardware and software technologies used for capsule endoscopy and remote patient monitoring. We introduce the structure and functions of the gastrointestinal tract, and the FDA guidelines for ingestible wireless telemetric medical devices. We survey the advanced features incorporated in ingestible capsule systems, such as microrobotics, closed-loop feedback, physiological sensing, nerve stimulation, sampling and delivery, panoramic imaging with adaptive frame rates, and rapid reading software. Examples of experimental and commercialized capsule systems are presented with descriptions of their sensors, devices, and circuits for gastrointestinal health monitoring. We also show the recent research in biocompatible materials and batteries, edible electronics, and alternative energy sources for ingestible capsule systems. The results from clinical studies are discussed for the assessment of key performance indicators related to the safety and effectiveness of ingestible capsule procedures. Lastly, the present challenges and outlook are summarized with respect to the risks to health, clinical testing and approval process, and technology adoption by patients and clinicians.