Plastic optical fiber

This study reports use of inexpensive intensity‐based plastic optical fiber (POF) in the form of cantilever beam to monitor the force. The cantilever consists of POF surface bonded on the surface of metal beams viz. spring steel (SS) and mild steel (MS) and subjected to force. The performance of the force sensor is evaluated during macro‐bending caused because of the deflection of the beam by applied force. Experimentally obtained detector output of POF, which could be measured with negligible hysteresis is compared with finite element analysis in the range between 0.0098 and 19.613 N. The reproducibility of the sensor is observed in the limit of ±1%. The proposed sensor can replace stain gauge load cell to certain extent in some applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1020–1023, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24217

This work establishes computational analysis of relative refractive index property for light transmission via fiber optics using MATLAB simulation. Optical fiber is a dielectric wave guide which transmits signal with a low attenuation and dispersion at higher bandwidth or data rate. Recent advances in fiber optics introduced a largely new dimension into optical technology with the effect of improving transmission through the application of cladding system. Cladding in fiber communication is importantly applied to ease light transmission in the fiber-core interface by total internal reflection at the boundary between two light propagation region of a typical fiber. Optical fiber communication is a well recognized aspect of optical light transmission where clad fibers of different refractive indices recount for a measurable Numerical aperture and Acceptance angle in fiber networking and communication technology. This has lead to the efficient and effective optical transmission due to the adequate emergence and utilization of optical properties and parameters in optical fiber applications. A double cladding was set for the fiber and a maximum relative refractive index of 2.000% is obtained for an acceptance angle and numerical aperture range of 59°-64° and 0.859-0.900 respectively. This implies fast light transmission, high bandwidth and small bending sensitivity for fiber networking with applications in medicine and telecommunication compared to single cladding fiber.

The goal of this project is to design and analyse a radio over fibre system for a four-story hospital with 20 rooms on each floor. The number of ONUs per floor is 20, and it was assumed that each room had an ONU capable of providing network access to voice, data, video, and biometrics. We build an 80-channel WDM optical transmitter using the WDM method. The proposed system includes a transmitter with 20 input channels, a multiplexer, a DE multiplexer, a 45-kilometer optical fibre, and an amplifier. The proposed model was simulated, and the results were evaluated in WDM systems using an optical amplifier. The receiver performance analysis of the Optical Communication System is shown by the BER simulation run and the eye diagram graphic, with the threshold set at 0.00120739. Furthermore, the eye height is 0.00141402, and the minimum BER is 5.59009e-006. When the simulated and calculated values of received power and total power loss are compared, the system is efficient.

A model is proposed to establish the relationship between the light coupling efficiency and fiber length for two contacted large fiber cores. The model correctly described the dependency of the coupled light on fiber length that was verified in the experiment with a twin-core fiber. This model can be used in fiber laser and erbium-doped fiber amplifier designs that employ twincore or multicore pumping.

Exposing an optical fiber core to the measurand surrounding the fiber is often used to enhance the sensitivity of an optical fiber sensor. This paper reports on the rapid fabrication of microstructures in an optical fiber using a CO₂ laser system which help exposing the optical fiber core to the measurand. The direct-write CO₂ laser system used is originally designed for engraving the polymeric material. Fabrications of microstructures such as in-fiber microhole, D-shaped fiber, in-fiber microchannel, side-sliced fiber and tapered fiber were attempted. The microstructures in the fibers were examined using a SEM and an optical microscope. Quality of microstructures shown by the SEM images and promising results from fluorescence sensor tests using in-fiber microchannels of 100μm width, 210μm depth and 10mm length show the prospect of this method for use in optical fiber sensor development. The direct-write CO₂ laser system is a flexible and fast machining tool for fabricating microstr...

Introduction During the last years, the standard step-index polymer optical fibre (SI-POF) with 1-mm core diameter has established itself as the preferred transmission medium for short-range optical data communications in automotive multimedia networks (MOST25/150) with data ...

This paper describes a multistandard fiber fed wireless system, which provides low-cost and enhanced performances regarding laser nonlinearity and RF transmitted power. Experimental results demonstrate that the proposed scheme provides not only optimized performances for low cost coming both from plastic optical fiber and vertical cavity surface emitting lasers (VCSELs), but also optimization of RF modulation power by complementary cumulative distribution function analysis and enhanced linear behavior by a whole new quasi-static approach of the VCSEL. With the help of those features, we successfully demonstrate minimization of error vector magnitude for simultaneous ultra-wideband multiband-orthogonal frequency division multiplexing and wireless local area network 802.11g optically transmitted signals and the possibility to use this system under conditions for symmetrical wireless communication. Index Terms-Complementary cumulative distribution function (CCDF), error vector magnitude (EVM), multiband-orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB), plastic optical fiber (POF), radio-over-fiber (RoF), vertical cavity surface emitting laser (VCSEL), wireless local area network (WLAN). I. INTRODUCTION T ODAY, higher and higher wireless data rate is required to give comfort to end users. Two main schemes for wireless in-home communications already exist: the IEEE 802.11 standard has being used since the end of the 1990s in wireless local area networks (WLANs), exhibiting a maximum data rate of 54 or 300 Mb/s with multiple input/output (MIMO) technology, and a coverage of about 100 m. Unfortunately, when one remote host uses a lower bit rate than the others, the performance of all hosts is considerably degraded [1]. IEEE 802.15.3c ultra-wideband (UWB) is an emerging technology for wireless personal area networks (WPAN), providing a high data rate-up to 480 Mb/s-but with a very small coverage, typically less than 10 m. This means that both solutions, WLAN and UWB, have to coexist for end users. Homes are being optically wired, if not already, to support digital traffic such as web navigation, video and audio broad-Manuscript

In this paper, we present a novel fabrication technique for constructing light focusing lenses, dielectric Fresnel zone plates on both flat wafers and tips of plastic optical fibers (POFs). SU-8 zone plate structures are made on glass substrate by photolithography with ink-printed soft mask, and then used as the template for hot embossing on the tip of PMMA POF. Focusing behavior for both 472 and 633 nm laser beams and LEDs in different colors are observed on glass wafers and POF tips, indicating that the proposed dielectric Fresnel zone plates can be built onto both substrate by a direct hot embossing process which may lead to a high volume production at low cost. Light intensity measurement on POFs proves that light focusing is achieved while intensity is maintained. This structure is expected to have broad applications in micro-imaging, micro-focusing as well as point-of-care medical surgeries.

Nowadays photonic crystal fiber is used for sensing liquid and solid materials. Here we used Hexagonal photonic crystal fiber (HPCF) for different animal’s milk sensing. Water, Camel Milk, Buffalo Milk, Cow Milk and Goat Milk are injected in core region one by one as sensing liquid and studied various sensing properties like external refractive index (ERI), Birefringence, comb-like profiled fiber (CPF), Aeff, Nonlinearity and Relative Sensitivity. The HPCF performance studied for different Parameters according to parameter when pitch is 7 micrometer to 10 micrometer and used various liquid, water, camel milk, buffalo milk, cow milk, goat milk respectively and for frequencies range 1.0 THz to 3.0 THz. When f = 1.5 THz, the relative sensitivity is studied 90.425%, 90.796%, 90.949%, 90.613% and 90.607% for Water, Camel Milk, Buffalo Milk, Cow Milk and Goat Milk respectively and when f=2.5 THz, the relative sensitivity is studied 92.329%, 92.891%, 93.243%, 92.513% and 92.587% for Water, Camel Milk, Buffalo Milk, Cow Milk and Goat Milk respectively. We found 179137 micrometer2, 181231 micrometer2, 182842micrometer2, 179597 micrometer2 and 179709 micrometer2 effective area respectively. Here we used full vector finite element method [FV-FEM] as a boundary condition. Here this Presented HPCF sensor is easy to fabricate using 3D printing technology.

This paper presents a proposed structure of Dual core photonic crystal fiber (DCPCF) along with a circular sensing ring for biochemical detection. Numerical analysis, Confinement loss and Relative sensitivity of PCF sensor have been observed for biochemical detection using Maxwell's equations with perfectly matched boundaries. The core region is filled with the patient's blood samples, and the light is confined through the core region. The circular sensing ring is utilized for trouble-free penetration to cope with biosensing applications. Since the occurrence of the blood samples is very in-differentiable in the human body, these sensors play a valuable role due to their trimness, small size, litheness, and isolated competence to identify diagonisive elements in human blood.

The district of Churu lies in the northeast of Rajasthan State at an altitude of 286.207 metres above the mean sea level. From geographical spread point of view it has extension from 27°24' to 29° north latitudes and 73°40' to 75°41' east longitudes. It is bounded by Hanumangarh in north, Bikaner in west, Nagaur in south and Sikar, Jhunjhunu districts and boundaries of Haryana State in the east. It covers six tehsils namely : Taranagar, Rajgarh, Churu, Sardarshahr, Ratangarh and Sujangarh. The plant species-Tecomella undulate (Rohida, Rohira, Rohido) belongs to the family-Bignoniaeeae. It is a medium to full tall sized tree and appears very beautiful during the time of full bloom period. Tree exibits the most beautiful flowers of area under study which starts from the month of January and remains upto April. Thus, it appears very ornamental during its flowering stage. It belongs to the vegetation group of tree. From life-forms point of view the tree comes in the group of 'microphanerophyte' but from the leaf-classes point of view it falls in the class of 'microphylls'. The observations over the survey sites as scattered in different habitats show the nature of distribution of Tecomella sp. in the area under study. Since, Tecomella species can survive and may prevail its life cycle in two or more habitats, it exhibits polyclimax tendency of plant succession It covers wide range of soluble salt contents i.e. from 200 to 10000 ppm. Churu locality of hilly areas is the last patch of Tecomella undulala association which is towards the extreme-arid region of area under study The wood of the tree is not preferred as a fuel but in lack of all other alternatives it is some times used as fuel. Although a good quality of coal may be produced by its wood. The leaves are evergreen and the tree afford a good fodder for goats and cattle.Its seeds and bark are used in some indigenous medicines as used by villagers at local importance. Due to strong beneficial factor, it is also known as 'desert teak'. A solid trunk of a mature tree has more local market value and is commercially sold at a large seale which ranges from 20000 to50000 rupees per tree. As compared to other western elements of this group, it has limited distribution in westward direction. Arabian countries i.e. Baluchistan, Sindh (Pakistan). Iraq and Iran, Saudi Arabia but it disappears gradually as one proceeds towards the Afriean continent. In our country, it occurs in the southwest of Siwalik range towards the plains of Punjab, western, northern Gujarat, extends upto northern Maharashtra state and Rajasthan-Churu, Jhunjhunu and Sikar.

Photonic crystal fibers (PCFs) are another type of optical fibres. Photonic crystal fibers (PCFs) are made with an internal periodic In this paper,we show design of elliptical air holes for getting zero dispersion.Here we use as2se3 glass as a PCF. Here we discuss how a core defect can be formed by manipulating the cladding region rather than the core region itself. There are so many difficulties occur during the design process. Because when parameters are being changed the designing varies accordingly. For this purpose we have use HPCF in scalar effective index method (SEIM) and consider chromatic dispersion of As2Se3 glass PCF.

In the conventional Photonic Crystal Fibers (PCFs), the cladding is formed by regular lattice of air holes with same diameter and silica glass is used as core material. In this paper, we have study a new structure of PCF filled Borosilicate Crown glass as core material. It is possible to control chromatic dispersion in wide wavelength range by varying the inner 3 layers hole diameter compare to outer 3 rings hole diameter. There are so many difficulties occur during the design process because when parameters are being changed the designing varies accordingly. Using this design principle, ultra flattened dispersion is also designed through a Scalar effective index method (SEIM) with Transparent Boundary Condition (TBC). Here we have also compare Borosilicate Crown glass PCF with Conventional silica glass PCF. A PCF with flat dispersion property may be very useful for next generation optical and communication data

This review paper gives an overview on Photonic Crystal Fiber (PCF) & its applications. Photonic Crystal Fiber is also known as micro structured or Holey fiber. Photonic crystal fiber is preferred over optical fiber because of its high design flexibility. Photonic crystal fiber is actually an optical fiber with a periodic arrangement of low index material in a background with high refractive index material. Light can be guided inside the PCF by either modified total internal reflection or photonic band gap guidance. Discussion of PCF in this paper includes its fabrication as well as application. Two methods namely "Stack and draw technique" & "Extrusion fabrication process" are used for the fabrication. PCF can be designed to get zero dispersion at required wavelength. PCF can be efficiently used in sensing applications using long period fiber grating (LPFG). LPFG can be fabricated using CO2 laser irradiation technique, which is preferred over interference method...

In this work, a novel high birefringent (HiBi) fiber loop mirror sensor based on a "figure-of-eight" constructed with a 3×3 fiber coupler, is presented. The "figure-of-eight" is formed by two fiber loop mirrors (FLM's) made by four of the six fiber arms of the 3×3 fiber coupler. The other two remaining fiber ports of the 3×3 coupler are used as input and output fibers of the compound sensor. The sensing head is located in the one of the FLM and it is formed by a spliced section of HiBi elliptical core fiber. The spectral response of this "figure-of-eight" configuration presents two interference optical signals that can be easily tuned by a polarization controller that is located in the other FLM, and which is made only of standard singlemode fiber from two arms of the 3×3 coupler. The sensor head was optically characterized both in temperature and strain, showing wavelength dependence sensitivities of-0.23 nm/ºC and-2.6 pm/με, for temperature and strain, respectively. It is noticed that these sensitivities are practically the same for the two interference signals. Future work will explore the possibility to use the singlemode FLM to interrogate the sensor head made by HiBi fiber section, and providing elimination of phase fluctuations that can occur, increasing its potential for remote sensing applications.

Fiber-optic daylighting systems have been shown to be a promising and effective way to transmit sunlight in the interior space whilst reducing electric lighting energy consumption. To increase efficiency in terms of providing uniform illumination in the interior, the current need is to illuminate optical fiber-bundle with uniform light flux. To this end, we propose a method for achieving collimated light, which illuminates the fiber-bundle uniformly. Light is collected through a parabolic concentrator and focused toward a collimating lens, which distributes the light over each optical fiber. An optics diffusing structure is utilized at the end side of the fiber bundle to spread light in the interior. The results clearly reveal that the efficiency in terms of uniform illumination, which also reduces the heat problem for optical fibers, is improved. Furthermore, a comparison study is conducted between current and previous approaches. As a result, the proposed daylighting system turns out convenient in terms of energy saving and reduction in greenhouse gas emissions.

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Exposing an optical fiber core to the measurand surrounding the fiber is often used to enhance the sensitivity of an optical fiber sensor. This paper reports on the rapid fabrication of microstructures in an optical fiber using a CO₂ laser system which help exposing the optical fiber core to the measurand. The direct-write CO₂ laser system used is originally designed for engraving the polymeric material. Fabrications of microstructures such as in-fiber microhole, D-shaped fiber, in-fiber microchannel, side-sliced fiber and tapered fiber were attempted. The microstructures in the fibers were examined using a SEM and an optical microscope. Quality of microstructures shown by the SEM images and promising results from fluorescence sensor tests using in-fiber microchannels of 100μm width, 210μm depth and 10mm length show the prospect of this method for use in optical fiber sensor development. The direct-write CO₂ laser system is a flexible and fast machining tool for fabricating microstr...

A novel solgel process for making porous silica fiber and doping the fiber core with sensing material is described. A CoCl 2-doped solgel fiber was fabricated and was used to construct an active-core optical fiber moisture sensor. Test results show that the sensitivity of the active-core optical fiber sensor is much higher than that of an evanescent-wave-based optical fiber sensor.

A dual-parameter fiber sensor achieved by cascading a fiber Bragg grating with a no-core fiber (NCF) is used for simultaneously detecting both the temperature and index physical parameters. The main index sensing mechanism of NCF is based on the wavelength shift of multimode signals' interference (MMI), and the temperature-sensing mechanism is determined by the Bragg wavelength shift and MMI wavelength shift. As the testing index value approaches the cladding index of the optical fiber, an MMI-induced loss-dip is thus created with a sensitivity of 899 nm∕RIU due to the phase-match condition of MMI being satisfied. By coating the thin films of different materials, this kind of sensor can be applied in a wide range of different sensing systems. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Fiber-optic daylighting systems have been shown to be a promising and effective way to transmit sunlight in the interior space whilst reducing electric lighting energy consumption. To increase efficiency in terms of providing uniform illumination in the interior, the current need is to illuminate optical fiber-bundle with uniform light flux. To this end, we propose a method for achieving collimated light, which illuminates the fiber-bundle uniformly. Light is collected through a parabolic concentrator and focused toward a collimating lens, which distributes the light over each optical fiber. An optics diffusing structure is utilized at the end side of the fiber bundle to spread light in the interior. The results clearly reveal that the efficiency in terms of uniform illumination, which also reduces the heat problem for optical fibers, is improved. Furthermore, a comparison study is conducted between current and previous approaches. As a result, the proposed daylighting system turns out convenient in terms of energy saving and reduction in greenhouse gas emissions.

Concrete is a composite material composed of coarse granular material (the aggregate or filler) embedded in a hard matrix of material (the cement or binder) that fills the space among the aggregate particles and glues them together. Translucent concrete is a concrete based building material with light-transmitting properties due to embedded light transmitting materials. Due to the small size of the fibres, they blend into concrete becoming a component of the material like small pieces of aggregate. This research work aims at investigating the effect of optic fibres on the strength and translucent properties of concrete. Fibre optics were introduced into the concrete mix as an optical material to enhance the translucency of concrete. The fibre optics were introduced at 2, 4 and 6% replacement level of fine aggregate. Compressive and translucency tests were carried out on the samples. From the test results it was observed that the compressive strength of translucent concrete increased by 4.3, 11.8 and 27.1% at 2, 4 and 6% optic fibre content respectively. The translucent concrete exhibited translucency property at different optic fibre content. The more the optic fibre the more translucency achieved as shown in the experimental result for example 135.26 lux at 6%, 85 lux at 4% and 55 lux at 2%.

We present an interferometric setup for in situ monitoring of fiber tip positions when inserting optical fibers for fixation in fiber connector components. It ensures an accurate fiber tip position at the fiber connector's front facet and across the fiber array in cases where postinsertion polishing is not possible. We demonstrate our technique by populating a plastic fiber connector for optical interconnect applications, and compare the fiber tip position measured in situ using our setup with the position measured off-line using a commercial white light interferometer, showing a deviation smaller than 5%.

High performance self-consolidating concrete HP-SCC is one of the most complex types of concrete which have the capacity to consolidated under its own weight, have excellent homogeneity and high durability. This study aims to focus on the possibility of using industrial by-products like Silica fumes SF in the preparation of HP-SCC enhanced with discrete steel fibers (DSF) and monofilament polypropylene fibers (PPF). From experimental results, it was found that using DSF with volume fraction of 0.50 %; a highly improvements were gained in the mechanical properties of HP-SCC. The compressive strength, splitting tensile strength, flexural strength and elastic modulus improved about 65.7 %, 70.5 %, 41.7 % and 80.3 % at 28 days age, respectively with retaining the main properties of HP-SCC. Furthermore, using PPF with volume fraction up to 0.10 %; an enhancement in the compressive and elastic modulus of HP-SCC about 47.4 % and 31 % was obtained at age of 28 days, respectively. Moreover, ...

ABSTRACT The influence of microbends on a phase shift and attenuation in a classical Corning SMF-28 fiber and in a special microstructured single-mode fiber with a limited number of air-hole rings in the cladding has been investigated. The largest measured phase shift of 750 deg/mm was obtained for the classical fiber at displacement magnitude of 117 mum. This corresponds to 1.3×10-3 change in the effective refractive index of the fundamental LP01 mode in a microbent optical fiber section with length of 24 mm. The phase shift for the investigated microstructured fibers is in 3.9 times less. The cutoff of radiation intensity takes place at displacement magnitudes of 55 and 270 mum for the microstructured fiber and for the SMF-28 fiber, respectively. It is shown that the sensitivity of the microstructured fiber to the displacement magnitude is in about five times higher than that of the Corning SMF-28 fiber.

This Engineering and Laboratory Note describes a simple, fast, cost-effective, and practical splicing technique for poly-methyl-methacrylate (PMMA) plastic optical fibers. We believe this technique can be useful for home networks, laboratory research, and educational uses. It employs a widely available, low-cost transparent adhesive combined with a suitable alignment sleeve. The fiber tips did not need to be cleaned or polished, and the polyethylene jacket did not need to be removed. The alignment between the cleaved fibers was performed by means of the jacket. Low insertion losses were measured for the main PMMA-based fiber types.

The use of a fluorescent fibre (15.5 mm in length) pumped in a forward direction with a 520 nm emitting LED for fast wavelength conversion to 560 nm is reported. In addition to the fact that this wavelength matches the attenuation minima of poly-methyl-methacrylate polymer optical fibres (POFs), the presented results show an external conversion efficiency of 4.7% and a bandwidth of 52.5 MHz. The device is a simple, inexpensive, compact, eye-safe and lightweight optical source at 560 nm. It can be suitable for single-channel 'long-distance' (>400 m) or WDM-based links using POFs, presenting a bandwidth-distance product of 50-100 MHz/100 m. Introduction: The C-band of silica optical fibres is centred at 1550 nm and covers the 1530-1565 nm wavelength range, presenting the minimum attenuation around 0.2 dB/km. Per-fluorinated (PF) polymer optical fibres (POFs) present minimum attenuation in an 850-1300 nm wavelength window. Suitable optical sources emitting in the near-infrared wavelengths (0.8-1.6 μm) are well developed and commercially available for silica fibres and PF POFs. Either step-index (SI) or graded-index poly-methyl-methacrylate (PMMA)-based POFs have four transmission windows assigned as blue, green, yellow/orange (560-600 nm) and red [1, 2]. However, the minimum attenuation band in the 560-600 nm wavelength range is quite underexplored for data communication links [1-4] due to the fact that semiconductor compounds such as GaAsP, AlGaInP and GaP:N cannot be used to produce relatively efficient and/or fast modulating optical sources at those wavelength range. Thus, WDM-over-POF links generally discard the use of yellow/orange channels [1, 2, 5].

Because it is the most ubiquitous species encountered in chemical reactions, hydrogen ion
occupies a very special place in chemistry and biology, most of the chemical and biological
processes being dependent on its activity. From the analytical point of view, the abundance
of hydrogen ions is quantified in terms of pH, the negative logarithm of its activity. Its
importance is evident by considering that, if the pH of the human blood changes as little as
0.03 pH units or less, the functioning of the body will be greatly impaired; also, brain pH
decreases from normal pH of 7.4 to a pH of 6.75 during the brain insult and a continuous
monitoring system would be beneficial in the treatment of comatose neurosurgical patients
and those who have suffered traumatic brain injury, ischemic brain insult and so forth
(Zauner, 1995). Furthermore, the kind of animals and plants living in lakes, rivers and
oceans depends on pH values, as well as pH of soil affects the livability of plants. For this
reason, the use of pH sensors is widely diffused in various fields to monitor chemical and
biological processes and it is finding an increasing number of applications in medicine,
biomedicine, industry and environmental monitoring.

We report about three branch large core polymer power splitters optimized for connecting standard plastic optical fibers. A new point of the design is insertion of a rectangle-shaped spacing between the input and the central part of the splitter, which will ensure more even distribution of the output optical power. The splitters were designed by beam propagation method using BeamPROP software. Acrylic-based polymers were used as optical waveguides being poured into the Y-grooves realized by computer numerical controlled engraving on poly(methylmethacrylate) substrate. Measurement of the optical insertion losses proved that the insertion optical loss could be lowered to 2.1 dB at 650 nm and optical power coupling ratio could reach 31.8% : 37.3% : 30.9%.

An erbium doped fiber preform having a lead germanate erbium glass core with silica cladding was fabricated by a newly developed technique named "Core-Suction". This preform was then drawn into fiber and fiber cross-section, loss spectrum and refractive index profile measured. A 30 cm piece of the manufactured fiber was spliced to a standard silica fiber using a commercial available splicer. This spliced fiber was then used to setup an erbium doped fiber amplifier (EDFA) and gain spectrum of the amplifier measured. Distributed gain of the manufactured erbium fiber was measured using an optical frequency domain reflectometry (OFDR) based optical backscatter reflectometer (OBR). It is demonstrated that the "Core-Suction" technique can be used to make a high-gain amplifier that is compatible with conventional silica fibers.

We propose and experimentally demonstrate an orientation-dependent fiber-optic bending sensor. The sensing probe consists of a fiber Bragg grating inscribed in both the fiber core and the surrounding cladding of a section of a side-hole fiber. We utilized a side-illumination technique using a femtosecond laser to achieve the grating structure formation. The transmission intensities of both resonances are highly sensitive bending of the fiber, and the bending response shows orientation dependence. The surrounding temperature fluctuation causes a wavelength shift, but not an intensity variation. Therefore, the proposed sensor can be employed for simultaneous measurement of bending and temperature.

A temperature-independent reflective refractometer configuration based on a core-diameter-mismatch is proposed and experimentally demonstrated. The configuration consists of a short section of thin-core fiber (TCF) with a multimode fiber (MMF) tip inscribed with a fiber Bragg grating (FBG). The TCF excites cladding modes into the downstream MMF via the mismatch-core splicing interface, and the parts of the core and cladding modes are reflected back to the lead-in fiber core by the MFBG. The recoupling efficiency of the core and cladding modes is highly dependent on the surrounding refractive index (SRI) of the TCF and MMF. Experimental results show that some recoupled modes show a high sensitivity to SRI. Powerreferenced and temperature-independent SRI measurement with improved sensitivity for resolutions with SRI values near 1.33 is achieved through the wavelengths of selective mode monitoring.

We propose and experimentally demonstrate an orientation-dependent fiber-optic bending sensor. The sensing probe consists of a fiber Bragg grating inscribed in both the fiber core and the surrounding cladding of a section of a side-hole fiber. We utilized a side-illumination technique using a femtosecond laser to achieve the grating structure formation. The transmission intensities of both resonances are highly sensitive bending of the fiber, and the bending response shows orientation dependence. The surrounding temperature fluctuation causes a wavelength shift, but not an intensity variation. Therefore, the proposed sensor can be employed for simultaneous measurement of bending and temperature.

A temperature-independent reflective refractometer configuration based on a core-diameter-mismatch is proposed and experimentally demonstrated. The configuration consists of a short section of thin-core fiber (TCF) with a multimode fiber (MMF) tip inscribed with a fiber Bragg grating (FBG). The TCF excites cladding modes into the downstream MMF via the mismatch-core splicing interface, and the parts of the core and cladding modes are reflected back to the lead-in fiber core by the MFBG. The recoupling efficiency of the core and cladding modes is highly dependent on the surrounding refractive index (SRI) of the TCF and MMF. Experimental results show that some recoupled modes show a high sensitivity to SRI. Powerreferenced and temperature-independent SRI measurement with improved sensitivity for resolutions with SRI values near 1.33 is achieved through the wavelengths of selective mode monitoring.

A ray theory based on the time-independent Fokker-Planck equation and the integration of time along ray trajectories provides analytical expressions for the average arrival time and spread of optical pulses propagating in randomly distorted, multimode, optical fibres. A clear physical picture emerges from the theory. The analytical expressions obtained for (t) and (t 2) coincide with the ones obtained by Olshansky from coupled-mode theory. The (t 3) and (t 4) moments of the impulse response are also calculated. Simple closed-form formulae are given for the step-index slab. The coupling between all modes is effectively taken into account in our ray theory.

Conjugated luminescent polymers and oligomers, exhibiting stimulated emission (SE), are dispersed in polymethylmethacrylate (PMMA), films and optical fibers, either by blending or upon copolymerisation. With this PMMA doping, we aim to achieve gain and ultrafast optical switching. The modification of the dopant's chemical structure allows the tuning of the SE spectral region. Furthermore, we aim to achieve dopant chain isolation while maximising their concentration. In this paper, we present an overview of the research done in this area in the context of the European Union (EU)-funded research project "plastic optical fibers with embedded active polymers for data communications-POLYCOM".

A novel approach to an integral imaging system using a pliable plastic optical fiber array is proposed. The proposed system has the advantage that it can utilize a light source for three-dimensional (3D) images at an arbitrary location because the point light sources are formed by the plastic fiber array with flexible optical paths. Two-dimensional images can also be expressed in the proposed system. The light efficiency of this system is high compared with previous point light source array integral imaging systems. The feasibility of the proposed method is explained and demonstrated with experiments.

High-speed wireless communication is required to carrying out high-quality data. It can be realized by increasing data capacity with enlarging operational bandwidth. As we know, light has very large operational bandwidth with a drawback of large propagation loss in free-pace (air). Therefore, high-speed communication can be realized using light with short coverage area. Light has wide spectrum include visible light region. The visible light is used as a lamp for lighting in a room. The lamp with laser emitting diode (LED) is widely used due to its characteristics of low electric power consumption with bright light. Visible light for communication is promising for smart home. In here, we report our research activity to realize and demonstrate visible light communication with low-cost optoelectronic devices such as laser diodes and photo detectors. Demonstration of the short range visible light communication to carry out digital data is reported.

This paper examines the mechanical properties of a composite material made of modified Iraqi gypsum (juss) reinforced with polypropylene fibers. The modified juss was prepared by adding two percentages of cement (5, 10) %. Two percentages of polypropylene fibers were used, to reinforce the modified juss (1, 2) %. The water/dry compound ratio used was equal to 0.53%. The composite was evaluated based on compressive strength, flexural strengths, absorption percentage, density, acoustic impedance, ultra - pulse velocity, longitudinal shrinkage and setting time tests. The results indicated that the inclusion of cement on to juss increases the compressive strength, absorption percentage, density, acoustic impedance, ultra - pulse velocity, longitudinal shrinkage and a reduction in flexural strength and setting time were observed by adding the cement. In addition, the inclusion of polypropylene fiber was significant in improving mechanical performance of the composite material, it shows a...

We report on a novel electrical current-sensing principle based on wavelength-encoded modulation of the ultrabright green (at 525 nm) light-emitting diode transducers. It complies with the optical subsystem of a hybrid current transformer. Realtime wavelength demodulation is performed with the passive spectral edge filter OG 530. Linear calibration plots were achieved with 0 33 nm/mA for dc and +0 99 mA 1 for ac current sensitivity, respectively. A measurement accuracy of 1.3% for 28.4-mA ac peak current range is achieved. A simple theoretical model is outlined. Issues such as electronic and thermal effects on stability performance are also addressed.

Cells detection is crucial in microbiological analysis of clinical, food, water or environmental samples. However, currently employed methods are time consuming. Plastic optical fiber (POF) biosensors consist in a viable alternative for rapid and inexpensive scheme for detection. In order to study the sensitivity of tapers for microbiological detection, geometric parameters are studied, such as the taper waist diameter since the formation of taper regions are the key sensing element in this particular type of sensors. In this study, a series of POF taper sensors were prepared using a specially developed tapering machine, and the dispersion of geometric dimensions is evaluated, aiming to achieve the best tapering characteristics which will provide a better sensitivity on the sensor response. The fiber tapers that presented the finest results were those constructed in U-shaped (bended) configurations, with taper waist diameters ranging from 0.40 mm up to 0.50 mm. These fiber tapers were used as the main section of the monitoring device, and when chemically treated as immunosensors for the detection of bacteria, yeast and erythrocytes.

This paper studies the production of sustainable and energy-saving concrete that can overcome the opaque nature of concrete with good strength properties. Consequently, this birthed translucent concrete. This study aimed to develop a detailed review of the properties and characteristics of translucent concrete, conduct some qualitative analysis on the concrete's potential light-transmitting abilities as well as its drawbacks and benefits translucent concrete, and make it accessible to scholars and researchers on this concrete type. The objective of this study was to review the properties of translucent concrete that have been studied by several researchers. To this study, it is believed that construction works with translucent concrete will be efficient and serve as a construction and economic breakthrough, specifically in low-income and low-middle-income nations where the cost of purchasing energy is high. A review assessment approach was used to examine past studies of translu...

Polymer Optical Fiber (POF) optical modules are gaining momentum due to their applications in short distance communications. POFs offer more flexibility for plug and play applications and provide cost advantages. They also offer significant weight advantage in automotive and avionic networks. One of the most interesting field of application is home networking. Low cost optical components are required, since cost is a major concern in local and home networks. In this publication, a fast and easy to install, low cost solution for efficient light coupling in and out of Step Index-POF is explored. The efficient coupling of light from a large core POF to a small area detector is the major challenge faced. We simulated direct coupling, lens coupling and bend losses for step index POF using ZEMAX R optical simulation software. Simulations show that a lensed fiber tip particularly at the receiver side improves the coupling efficiency. The design is optimized for 85% coupling efficiency and explored the low cost fabrication method to implement it in the system level. The two methods followed for lens fabrication is described here in detail. The fabricated fiber lenses are characterized using a beam analyzer. The fabrication process was reiterated to optimize the lens performance. It is observed that, the fabricated lenses converge the POF output spot size by one fourth, there by enabling a higher coupling efficiency. This low cost method proves to be highly efficient and effective optical coupling scheme in POF communications.