Plastic Optical Fiber Research Articles

THERMAL AND DAYLIGHTING PERFORMANCE OF TRANSPARENT CONCRETE IN PENANG, MALAYSIA

Modern technology studies and research developments have enhanced the quality and innovation of concrete. Transparent concrete is concrete that has light-transmitting properties which transmit light through the optical fibre. Optical fibres are reinforced in the conventional concrete mixture from one face to another face, which allows direct light to transmit through it. Daylighting factor is one of the fundamental qualities of the energy efficiency of a building. The thermal performance is also crucial to providing comfort to the building occupants. The literature studies cover the light transmittance and thermal performance of transparent concrete. Selected literature studies are reviewed based on the related topic, Asian countries, and countries with a similar climate to Malaysia. This research applies quantitative method where it was focus on experimental study to transparent concrete. The overall result indicates improvement on light transmission and thermal performance as the plastic optical fibre increased compared to conventional concrete. The total average outdoor surface temperature of transparent concrete shows a difference of 0.989°C lower than conventional concrete. The total average temperature different between conventional concrete and transparent concrete (560 optical fibre) are 0.9°C. This experiment's significant contribution is that using more plastic fibre optic reduces thermal conductivity and heat gain while allowing for greater daylighting. Finally, transparent concrete shows effectiveness on light transmission and thermal resistance where it can contribute to building industry on green building and sustainable design. However, the further studies on thermal performance with longer duration is required to analyses the thermal heat loss.

Multiple side-coupled images recognition in plastic optical fibers based on deep learning

In recent years, the technology of multi-mode fiber (MMF) output speckle recognition has been widely used in the fields of optical imaging, endoscope devices, and fiber optic sensor. However, previous studies focused on the single-input transmission mode on a single fiber, which limited the application range of MMF. Meanwhile, the fiber optic sensors based on speckle recognition often lack multiplexing ability. In this paper, multiple lateral sections of plastic optical fiber (POF) are polished, and the images corresponding to 26 letters are coupled into POF form them. When images couple into POF from one lateral polishing section, by analyzing the output speckles based on deep learning technology, the accuracy of speckles recognition with convolution neural network (CNN) reaches over 95% and the structural similarity (SSIM) of reconstructed speckles with U-Net reaches up to 0.96. When two images couple into POF from different lateral polishing sections simultaneously, the output speckle can be reconstructed to the two images respectively, and the average SSIM value for them is 0.95. The experiment proves that the images coupled into fiber through the lateral polishing section of POF can be recognized and reconstructed well by output speckle analysis. This technology can promote the multiplexing ability of the speckles-recognition based fiber sensors or be applied to the field of fiber endoscopes.

A Novel Approach to Realize Plasmonic Sensors via Multimode Optical Waveguides: A Review

In recent decades, the Surface Plasmon Resonance (SPR) phenomenon has been utilized as an underlying technique in a broad range of application fields. Herein, a new measuring strategy which harnesses the SPR technique in a way that is different from the classical methodology was explored by taking advantage of the characteristics of multimode waveguides, such as plastic optical fibers (POFs) or hetero-core fibers. The sensor systems based on this innovative sensing approach were designed, fabricated, and investigated to assess their ability to measure various physical features, such as magnetic field, temperature, force, and volume, and to realize chemical sensors. In more detail, a sensitive patch of fiber was used in series with a multimodal waveguide where the SPR took place, to alter the mode profile of the light at the input of the waveguide itself. In fact, when the changes of the physical feature of interest acted on the sensitive patch, a variation of the incident angles of the light launched in the multimodal waveguide occurred, and, as a consequence, a shift in resonance wavelength took place. The proposed approach permitted the separation of the measurand interaction zone and the SPR zone. This meant that the SPR zone could be realized only with a buffer layer and a metallic film, thus optimizing the total thickness of the layers for the best sensitivity, regardless of the measurand type. The proposed review aims to summarize the capabilities of this innovative sensing approach to realize several types of sensors for different application fields, showing the high performances obtained by exploiting a simple production process and an easy experimental setup.

Polymer Doping as a Novel Approach to Improve the Performance of Plasmonic Plastic Optical Fibers Sensors

In this work, Fe2O3 was investigated as a doping agent for poly(methyl methacrylate) (PMMA) in order to enhance the plasmonic effect in sensors based on D-shaped plastic optical fibers (POFs). The doping procedure consists of immerging a premanufactured POF sensor chip in an iron (III) solution, avoiding repolymerization and its related disadvantages. After treatment, a sputtering process was used to deposit a gold nanofilm on the doped PMMA in order to obtain the surface plasmon resonance (SPR). More specifically, the doping procedure increases the refractive index of the POF’s PMMA in contact with the gold nanofilm, improving the SPR phenomena. The doping of the PMMA was characterized by different analyses in order to determine the effectiveness of the doping procedure. Moreover, experimental results obtained by exploiting different water–glycerin solutions have been used to test the different SPR responses. The achieved bulk sensitivities confirmed the improvement of the plasmonic phenomenon with respect to a similar sensor configuration based on a not-doped PMMA SPR-POF chip. Finally, doped and non-doped SPR-POF platforms were functionalized with a molecularly imprinted polymer (MIP), specific for the bovine serum albumin (BSA) detection, to obtain dose-response curves. These experimental results confirmed an increase in binding sensitivity for the doped PMMA sensor. Therefore, a lower limit of detection (LOD), equal to 0.04 μM, has been obtained in the case of the doped PMMA sensor when compared to the one calculated for the not-doped sensor configuration equal to about 0.09 μM.

A plastic optic fiber sensor with temperature compensation for refractive index measurement

An optical fiber sensor based on a gradually hot-pressed flatted plastic optical fiber (POF) and F-P interference structure is proposed to eliminate the effect of ambient temperature drift in the refractive index (RI) detection of glucose concentration. Based on the analysis of the influence of the sensor itself and the RI change of solution on the transmitted light intensity under the effect of temperature, a self-calibration formula was established by means of the peak wavelength and the transmitted light intensity of interference peak were used as information carriers to calibrate the parameters. The results of the validation show that the temperature drift compensation method proposed in this paper is feasible. The maximum relative error between the measured RI after compensation and actual value is only 0.032%, and it has good repeatability. The precision to the RI with temperature compensation of the gradually hot-pressed flatted POF and F-P interference structure has potential applications in the biochemistry, medical diagnosis, and environmental monitoring.

Gold film effect on temperature compensation of a POF sensor with different structures.

In this paper, temperature compensation of plastic optical fiber (POF) is studied and gold absorbability is utilized. Gold film is modified on the surface of POF by magnetron sputtering. The temperature output characteristics of different structures such as ordinary (POF-N), side-polished (POF-SP), U-shaped (POF-U), and narrow groove structure (POF-NGS) are tested, and the effects of gold film thickness, polishing area, and sputtering sequence on the temperature output characteristics are also investigated. The power change of the sensor at different temperatures is recorded. The experimental results show that when the temperature is between 25°C and 50°C and the sputtering gold film thickness is 50nm, the temperature stabilities of POF-N, POF-U, POF-SP, and POF-NGS are 1.02µW/°C, 0.77µW/°C, 0.18µW/°C, and 0.35µW/°C, respectively. The compensation effect is enhanced as the gold film thickness increases. When the thickness is 100nm, the temperature stability of POF-NGS is 0.06µW/°C. The proposed temperature compensation method is competitive and straightforward.

Feasibility study on fiber-optic inorganic scintillator array sensor system for multi-dimensional scanning of radioactive waste

We developed a miniaturized multi-dimensional radiation sensor system consisting of an inorganic scintillator array and plastic optical fibers. This system can be applied to remotely obtain the radioactivity distribution and identify the radionuclides in radioactive waste by utilizing a scanning method. Variation in scintillation light was measured in two-dimensional regions of interest and then converted into radioactivity distribution images. Outliers present in the images were removed by using a digital filter to make the hot spot location more accurate and cubic interpolation was applied to make the images smoother and clearer. Next, gamma-ray spectroscopy was performed to identify the radionuclides, and three-dimensional volume scanning was also performed to effectively find the hot spot using the proposed array sensor.

Ammonia detection in water with balloon-like plastic optical fiber sensor

This work presents the demonstration of a plastic optical fiber (POF)-based ammonia sensor. The sensor head is formed by bending an unclad fiber optic sensor into a balloon-like structure. The bending radius of the balloon-like bent fiber optic sensor is varied from 1.0 to 2.5 cm. The performance of each sensor is tested using ammonia solution with concentration ranging from 0 to 15 mg l−1. Results show that the optimized performances of the proposed sensor occur when the bending radius is fixed at 1.5 cm. At this bending radius, the sensor illustrates the sensitivity of − 0.0024 (mg/l)−1 with linearity of 0.97 and resolution of − 4.17 mg l−1. For comparison, the bent sensor is compared to the straight sensor and performances of the former is found to be more superior. In addition, the balloon-like bent sensor is further tested with real water samples. The sensor sensitivity is found to be − 0.0022 (mg/l)−1 with linearity of 0.95 and resolution of − 4.54 mg l−1. The result shows that the sensor has comparable performance in the ammonia detection for both pure ammonia and real water samples. In essence, this balloon-like bent sensor functions without additional coating on the sensor head, making it favorable in terms of the simplicity of the design.

Passive OFE WDM-over-POF Gigabits per Second Performance Comparison of Spatial Diversity and Spatial Multiplexing

We present a novel indoor communication network using 1-mm core diameter step-index plastic optical fibres as a feeder line, and using the light emitted by the POF-end for wireless data transmission, creating a fully passive access point (AP). This has the advantage that it does not require electrical powering, resulting in low maintenance. Due to the large numerical aperture, the light emitted by the POF is extremely divergent, thus a lens must be placed in front of the POF-end to adjust the size of the coverage area to enable users moving within the area or to increase the number of users served by the wireless link. We present a theoretical model for both multiple-input multiple-output (MIMO) transmission modes, spatial diversity (SD) and spatial multiplexing (SM) concepts, using orthogonal frequency division multiplexing (OFDM). We report the system throughput, that is estimated using the singular value decomposition (SVD) of the experimentally measured channel matrix <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {H}(f)$</tex-math></inline-formula> . We then present the experimental results applying both SD and SM concepts and make a comparison between theoretical and experimental results. We demonstrate that this passive AP concept using OFDM achieves throughputs of around 5.2 Gbps when SM is applied, and 3.8 Gbps when SD is applied. Furthermore, we use eye-safe visible light laser at the beginning of the POF feeder which, due to optical losses by POF and components, limited the wireless link to 1 m only and the coverage area to 45 cm diameter. We believe the proposed system represents a low-cost, high-capacity, highly secure, interference free wireless system, suitable for next generation for industrial and home applications.

A Novel Microchannel-in-a-Fiber Plasmonic Sensor

In this work, a novel Surface Plasmon Resonance (SPR) sensor has been designed, realized and investigated. The SPR platform was created by using a D-shaped plastic optical fiber shell (POFS), obtained by removing the graded index core region from the fiber’s protective jacket, in order to create a microchannel. The latter was then coated with a gold nanofilm in order to obtain the plasmonic sensitive region. The sensor’s structure includes an integrated measuring cell, being the solution under test injected into the microchannel using a peristaltic pump. The microchannel dimension (160 μm) allows to avoid microfluidic systems, typically adopted in this kind of SPR configurations. As a proof of concept, the plasmonic sensor has been tested as a refractometer using different water-ethanol solutions, with a refractive index range from 1.332 to 1.352. The experimental results have highlighted a sensitivity and a resolution equal to about 1026 nm/RIU and 1.95 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> RIU, respectively. These values testify to the proposed sensor goodness and its suitability for biochemical sensing applications.

Performance evaluation of plastic optical fiber communication using micro-lens coupling and computational temporal ghost imaging algorithm.

Plastic optical fiber communication (POFC) systems are particularly sensitive to signal performance and power budget. In this paper, we propose what we belive to be a novel scheme to jointly enhance the bit-error-ratio (BER) performance and coupling efficiency for multi-level pulse amplitude modulation (PAM-M) based POFC systems. The computational temporal ghost imaging (CTGI) algorithm is developed for PAM4 modulation for the first time to resist the system distortion. The simulation results reveal that enhanced BER performance and clear eye diagrams are acquired by using CTGI algorithm with an optimized modulation basis. Experimental results also investigate and show, with CTGI algorithm, the BER performance for 180 Mb/s PAM4 signals is enhanced from 2.2 × 10-2 to 8.4 × 10-4 over 10 m POF by using a 40 MHz photodetector. The POF link is equipped with micro-lenses at its end faces by using a ball-burning technique, which helps to increase the coupling efficiency from 28.64% to 70.61%. Both simulation and experimental results show that the proposed scheme is feasible to achieve a cost-effective and high-speed POFC system with short reach.

An optical fiber-based point-of-care test for periodontal MMP-8 detection: A proof of concept

ObjectivesThe evaluation of salivary biomarkers has been proposed as a simple and non-invasive aid to the conventional periodontal diagnosis based on clinical-radiographic parameters. Matrix metalloproteinase-8 (MMP-8), especially in its active form, is considered one of the most reliable biomarkers of periodontitis, and point-of-care tests (POCTs) have been proposed for its clinical monitoring. In this proof-of-concept study, a novel highly sensitive POCT based on a plastic optical fiber (POF) biosensor exploiting surface plasmon resonance (SPR) to detect salivary MMP-8 is described. MethodsA SPR-POF biosensor was functionalized with a specific antibody to develop a surface-assembled monolayer (SAM) for the detection of total MMP-8. A white light source and a spectrometer connected to the biosensor were used to quantify MMP-8 level in both buffer and real matrix (saliva) by analysing the shift of the resonance wavelength determined by the specific antigen-antibody binding upon the SAM. ResultsDose-response curves by serial dilutions of human recombinant MMP-8 were realized, obtaining a limit of detection (LOD) of 40 pM (1.76 ng/ml) in buffer and 225 pM (9.9 ng/ml) in saliva and high selectivity compared to interferent analytes (MMP-2 and IL-6). ConclusionsThe proposed optical fiber-based POCT was able to detect and measure total MMP-8 with high selectivity and very low LOD in both buffer and saliva. Clinical significanceThe SPR-POF technology may be employed to create highly sensitive biosensors to monitor salivary MMP-8 levels. The possibility of specifically detecting its active, rather than total, form need to be further investigated. If confirmed and clinically validated, such a device may represent a promising tool to make an immediate, highly sensitive and reliable diagnosis of periodontitis, and to carry out a timely and targeted therapy, possibly helping to prevent the onset of local and systemic periodontitis-related complications.

Polyaniline coated plastic optic fiber biosensor for detection of aflatoxin B1 in nut, cereals, beverages, and body fluids

Detection of aflatoxin B1 (AFB1) in environmental samples and body fluids is necessary for taking effective precautions and treatment of contamination. Its invisible presence is also associated with huge economic losses to nations. Plastic optical fiber (POF) offers a cost-effective yet flexible waveguide for visible light to develop optical biosensors. We have developed an ultrasensitive POF based AFB1 sensor that operates from pico to micromolar concentration with reasonable accuracy (R2 = 0.99). AntiAFB1 antibody has been used as bioreceptor for the sensor. The optical property of polyaniline (PAni) has been explored on polymethylmethacrylate (PMMA) surfaces of POF for the fabrication of a simple, inexpensive, yet highly sensitive AFB1 biosensor. The evanescent wave absorbance-based sensor was able to detect analytes below the maximum permissible residual limit (MRL) set by any country for spiked peanuts, corn, wheat, and beer. The sensor was further optimized to detect AFB1 in spiked human serum and urine within the pathological relevance. The recovery results fell between 81 % and 117 %, demonstrating reasonable accuracy. The matrix factor of different real matrices lies within around 0.85–1.14, i.e., within the acceptable range.

A Comparative Study of Plastic and Glass Optical Fibers for Reliable Home Networking

Home networking using fiber optics is essential for uninterrupted data transmission in modern communication networks. In this study, we evaluated and compared the reliability of plastic optical fibers (POFs) and glass optical fibers (GOFs) for home networking applications. Furthermore, assess the advantages and disadvantages of POF and GOF over short distances and find that POF is more suitable for home network applications due to its higher reliability. In addition, it has the advantage of being cost-effective and flexible for short-distance applications. The results show that POF indicates higher reliability and better performance at 8.25517 × 101of the Q factors, 2.21355 × 10−3 of the eye height, and 2.8307 × 10−3 of the threshold values at 30 meters, while GOF shows 6.30 × 101 of the Q factor, 3.78087 × 10−3 of the eye heights and 4.34736 × 10−3 of the threshold values. Moreover, this research highlights the importance of reliability in designing and applying optical fiber networks and can help network designers and engineers make informed decisions when selecting the appropriate type of optical fiber for specific applications.

Fusion splicing of plastic optical fibers using a mid-IR fiber laser

This work demonstrated the fusion splicing of plastic optical fibers (POFs) using a 2.8 μm continuous-wave fiber laser. This mid-IR laser-based fusion splicing technique does not require the use of adhesives or any other treatments. The performance of the proposed method was investigated by assessing the optical transmission, tensile strength and bending strength values of POF specimens after fusion bonding while employing various splicing conditions. An optical transmission of 0.76 was obtained by splicing under appropriate conditions. A minimum bending radius and tensile strength of the POF samples were found to be 1.5 mm and 13.5 N, respectively.

Bandwidth Analysis of High-Speed InGaN Micro-LEDs by an Equivalent Circuit Model

High-speed light-emitting diodes (LEDs) are ideal light sources for low-cost plastic optical fiber communication in data-centers and vehicles. Here, high-speed micro-LEDs based on InGaN quantum dot (QD) active region with different diameters are fabricated and characterized. The -3dB bandwidth around 3.6 GHz and 1.4 GHz are achieved in the blue and green micro-LEDs under current density less than 1 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively, which can work at an environmental temperature of 125 °C. An equivalent circuit model is proposed to analyze the limiting factors of the bandwidth, using which the effects of carrier recombination and RC time constant on modulation bandwidth are separated. It is found that carrier recombination rate is fast enough and the RC constant is still the main limiting factor for the blue micro-LEDs at an injection current density of more than 500 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> even when the diameter scales down to 20 μm, while the recombination rate mainly limits the bandwidth of the green micro-LEDs.

Study of a TiO2/Ti4O7-coated plastic optic fiber photo-anode for advanced oxidation processes

Study of a TiO2/Ti4O7-coated plastic optic fiber photo-anode for advanced oxidation processes

Illumination of Interior Spaces through Structures Made of Unified Slabs of High-Performance Light-Transmitting Concrete with Embedded Optical Fibers.

Light-transmitting concrete as a building material already exists in many forms, but its light properties and the possibilities of using it to improve the lighting of interior spaces have not been investigated in detail yet. This paper focuses on the illumination of interior spaces using constructions made of light-transmitting concrete, which will allow light to pass between individual spaces. The experimental measurements carried out are divided into two typical situations using reduced room models. The first part of the paper focuses on the illumination of the room through the penetration of daylight through the ceiling made of light-transmitting concrete. The second part of the paper investigates the transmission of artificial light from one room to another through a non-load-bearing dividing structure composed of unified slabs of light-transmitting concrete. For the experiments, several models and samples were created for comparison. The first step of the experiment was to create slabs of light-transmitting concrete. While there are many options to produce such a slab, the best option is to use high-performance concrete with glass-fiber reinforcement, which improves the load transfer properties, and plastic optical fibers for light transmission. By adding optical fibers, we can achieve the transmission of light between any two spaces. For both of the experiments, we used reduced-scale models of rooms. Slabs with dimensions of 250 × 250 × 20 mm and 250 × 250 × 30 mm were used in three versions: concrete slabs with optical fibers, concrete slabs with air holes and solid slabs. The experiment measured and compared the level of illumination at several points in the model as it passed through each of the three different slabs. Based on the results of these experiments, it was concluded that the interior level of illumination of any space can be improved by using light-transmitting concrete, especially those without access to natural light. The experiment also assessed the strength properties of the slabs in relation to their intended use and compares them with the properties of stone slabs used as cladding.

Two-Wavelength Dye-Doped Swellable Clad POF Humidity Sensor

Because humidity is an important indicator used in many fields, the development of technology for its measurement is of great significance. We investigated humidity sensors that use a swellable polymer as the cladding material of plastic optical fibers (POFs). A POF humidity sensor using hydroxyethyl cellulose (HEC) as the cladding material has a linear response at approximately 20% relative humidity (RH), but its sensitivity is low. The sensitivity can be improved by adding brilliant blue (BB) as a dye to cladding. However, this makes the detection range of the sensor too narrow for practical use. Therefore, we change the incident light from a single wavelength to two wavelengths and use the fact that the output waveform of the dye-doped sensor depends on the wavelength of the incident light. The results of experiments show that a humidity sensor with high sensitivity and an RH detection range of 10%–90% can be developed by combining the output waveforms of a two-wavelength sensor with a dye doping level of 0.8% in cladding.

A novel examination of limonene detection using plastic fiber optic sensors and the tapered approach

A novel tapered plastic optic fiber (POF) biosensor is proposed and demonstrated for monitoring limonene in different concentrations. The mechanism of this device is based on an increase in the light transmission of a sensor submerged in a higher-concentration limonene solution, which also reflects an increase in the refractive index of the sensor. The tapered POF was fabricated using the chemical etching method to accomplish different waist diameters of 0.6 mm, 0.55 mm, and 0.5 mm, with a fiber length of 10 cm and a 2 cm sensing region. An Arduino integrated development environment (IDE) program was used to drive the voltage values from the photodetectors to obtain the measurements. As the limonene concentration solution varied from 20% to 100%, the output voltage of the sensor increased linearly, showing a sensitivity of 0.295 V/%, 0.33 V/%, and 0.46 V/% for tapered waist diameters of 0.6 mm, 0.55 mm, and 0.5 mm, respectively. The proposed sensor is a low-cost solution measurement option with high sensitivity, while it also involves a simple and easy fabrication technique.