Inscription of narrow bandwidth bragg gratings in polymer optical fibers

We report on the production and characterization of narrow bandwidth fiber Bragg gratings (FBGs) in two spectral regions using polymer optical fibers (POFs). Narrow bandwidth FBGs are increasingly important for POF transmission systems, WDM technology and sensing applications. Long FBGs with resonance wavelength around 850 nm and 1550 nm were fabricated in several types of polymer optical fibers. The 3 dB FBG bandwidth varies from 0.22 nm down to 0.045 nm considering a Bragg grating length of 10 mm and 25 mm, respectively. © 2013 SPIE.

A fast response intrinsic humidity sensor based on an etched singlemode polymer fiber Bragg grating

A simple, low cost and fast response time intrinsic relative humidity sensor system based on an etched singlemode polymer fiber Bragg (POFBG) is presented in this paper. A macro-bend linear edge filter which converts the humidity induced wavelength shift into an intensity change is used as the interrogation technique. The singlemode POFBG is etched to micro-meters in diameter to improve the response time of the humidity sensor. A response time of 4.5 s is observed for a polymer FBG with a cladding diameter of 25 μm. The overall sensor system sensitivity was 0.23 mV/%RH. The etched POFBG humidity sensor shows anexponential decrease in response time with a decrease in fiber diameter. The developed sensor might have potential applications in a wide range of applications where fast and accurate real time humidity control is required. © 2013 Elsevier B.V. All rights reserved.

Effects of annealing, pre-tension and mounting on the hysteresis of polymer strain sensors

When exposed to high levels of strain, polymer optical fibre grating sensors recorded in poly(methyl methacrylate) based fibre often exhibit hysteresis in the response of their Bragg wavelength to strain. We demonstrate that the application of pre-tension and annealing of the polymer fibre can reduce this hysteresis when the fibre is suspended freely between two supports, but much better performance is obtained when the sensor is attached directly to a substrate. In this case, the hysteresis can be lessened by more than a factor of 12. © 2014 IOP Publishing Ltd.

Narrow bandwidth Bragg gratings imprinted in polymer optical fibers for different spectral windows

The production and characterization of narrow bandwidth fiber Bragg gratings (FBGs) in different spectral regions using polymer optical fibers (POFs) is reported. Narrow bandwidth FBGs are increasingly important for POF transmission systems, WDM technology and sensing applications. Long FBGs with resonance wavelength around 600-nm, 850-nm and 1550-nm in several types of polymer optical fibers were inscribed using a scanning technique with a short optical path. The technique allowed the inscription in relative short periods of time. The obtained 3-dB bandwidth varies from 0.22 down to 0.045 nm considering a Bragg grating length between 10 and 25-mm, respectively. © 2013 Elsevier B.V.

Polymer optical fibre Bragg gratings

This paper provides a review of the current state of research and development into polymer fibre Bragg gratings, along with a description of some current challenges. © 2012 OSA.

Measuring water activity of aviation fuel using a polymer optical fiber Bragg grating

Poly(methyl methacrylate) (PMMA) based polymer optical fiber Bragg gratings have been used for measuring water activity of aviation fuel. Jet A-1 samples with water content ranging from 100% ERH (wet fuel) to 10 ppm (dried fuel), have been conditioned and calibrated for measurement. The PMMA based optical fiber grating exhibits consistent response and a good sensitivity of 59±3pm/ppm (water content in mass). This water activity measurement allows PMMA based optical fiber gratings to detect very tiny amounts of water in fuels that have a low water saturation point, potentially giving early warning of unsafe operation of a fuel system. © 2014 SPIE.

Polymer degradation and stability

This edition of Polymer Degradation and Stability is dedicated to papers which were presented in the session on ‘Chemical Modification’ at the Third International Conference on Modification Degradation and Stabilisation of Polymers (MoDeSt) held in Lyon in August 2004. This was the third meeting of the MoDeSt Society which was set up in the year 2000 under the chairmanship of Professor Franco LaMantia; the earlier meetings were held in Palermo (2000) and Budapest (2002). The overall goal of the MoDeSt Society is to promote the latest research carried out in University laboratories, in public organisations and in industry through publications, and organisation of biannual scientific conferences and workshops that act as forums for scientific developments and for promoting networking between academics and industrialists from across the field of polymer modification, degradation and stabilisation. In September 2004, Professor Norman Billingham was elected as Chairman of the Society. The conference was organised by Dr Alain Michel and Veronique Bounor-Legare of the University Claude Bernard, Lyon 1, attracting over 250 delegates with the ‘Chemical Modification’ Session alone enjoying 54 oral presentations and many more poster presentations. We are all very grateful to the organisers for running such a successful and enjoyable meeting. I wish to thank my co-editors, Professors Philippe Dubois and Domenico Acierno and Dr Alain Michel, for their cooperation in the editorial task of the papers published in this special issue. On behalf of the editors of this issue, I wish to express our appreciation to the Editor-in-Chief of Polymer Degradation and Stability, Professor Norman Billingham, for the support and help received during the preparation of this special issue.

Erbium doped fiber laser mode locked by graphene in carboxymethylcellulose polymer composite

We have presented and demonstrated efficient mode locking of erbium doped fiber laser using graphene carboxymethylcellulose (CMC) polymer composites. The laser gives out soliton pulse with duration of ∼837 fs, and 0.19 nJ pulse energy. © 2014 OSA.

10 Mb/s visible light transmission system using a polymer light-emitting diode with orthogonal frequency division multiplexing

We present a newly designed polymer light-emitting diode with a bandwidth of ∼350 kHz for high-speed visible light communications. Using this new polymer light-emitting diode as a transmitter, we have achieved a record transmission speed of 10 Mb/s for a polymer light-emitting diode-based optical communication system with an orthogonal frequency division multiplexing technique, matching the performance of single carrier formats using multitap equalization. For achieving such a high data-rate, a power pre-emphasis technique was adopted. © 2014 Optical Society of America.

Demountable connection for polymer optical fiber grating sensors

The authors fabricated a demountable Ferrule connector/Physical contact connection between silica fiber and a polymer optical fiber (POF) containing a fiber Bragg grating. The use of a connector for POF grating sensors eliminates the limitations of ultraviolet glued connections and increases the ease with which the devices can be applied to real-world measurement tasks. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

Effects of ball-milling on PLGA polymer and its implication on lansoprazole-loaded nanoparticles

PLGA is a biodegradable polymer utilised widely in pharmaceutical research for the encapsulation of a wide range of drugs as nano particulate systems. This study investigates the impact of rotary ball milling on the physical properties of PLGA and its influence on nanoparticle formation prepared using the solvent displacement technique. By applying mechanical stress to the polymer and altering its physical appearance and molecular weight, the loading of lansoprazole within the nanoparticles was increased to 96%, with a reduction in particle size. The results indicate that rotary ball milling significantly reduces particle size, increases lansoprazole loading and improves the release profile for lansoprazole loaded PLGA nanoparticles.

Through-thickness plasma modification of biodegradable and nonbiodegradable porous polymer constructs

Pure poly(lactide-co-glycolide) and polystyrene surfaces are not very suitable to support cell adhesion/ spreading owing to their hydrophobic nature and low surface energy. The interior surfaces of large porous 3D scaffolds were modified and activated using radio-frequency, low-pressure air plasma. An increase in the wettability of the surface was observed after exposure to air plasma, as indicated by the decrease in the contact angles of the wet porous system. The surface composition of the plasma-treated polymers was studied using X-ray photoelectron spectroscopy. pH-dependent zeta-potential measurements confirm the presence of an increased number of functional groups. However, the plasma-treated surfaces have a less acidic character than the original polymer surfaces as seen by a shift in their isoelectric point. Zeta-potential, as well as contact angle measurements, on 3D scaffolds confirm that plasma treatment is a useful tool to modify the surface properties throughout the interior of large scaffolds. © 2008 Wiley Periodicals, Inc.

A 20-Mb/s VLC link with a polymer LED and a multilayer perceptron equalizer

This letter experimentally demonstrates a visible light communication system using a 350-kHz polymer lightemitting diode operating at a total bit rate of 19 Mb/s with a bit error rate (BER) of 10-6and 20 Mb/s at the forward error correction limit for the first time. This represents a remarkable net data rate gain of ~55 times. The modulation format adopted is ON-OFF keying in conjunction with an artificial neural network classifier implemented as an equalizer. The number of neurons used in the experiment is varied from the set N = {5, 10, 20, 30, 40} with 40 neurons offering the best performance at 19 Mb/s and the BER of 10-6.

Atmospheric plasma treatment of porous polymer constructs for tissue engineering applications

Porous 3D polymer scaffolds prepared by TIPS from PLGA (53:47) and PS are intrinsically hydrophobic which prohibits the wetting of such porous media by water. This limits the application of these materials for the fabrication of scaffolds as supports for cell adhesion/spreading. Here we demonstrate that the interior surfaces of polymer scaffolds can be effectively modified using atmospheric air plasma (AP). Polymer films (2D) were also modified as control. The surface properties of wet 2D and 3D scaffolds were characterised using zeta-potential and wettability measurements. These techniques were used as the primary screening methods to assess surface chemistry and the wettability of wet polymer constructs prior and after the surface treatment. The surfaces of the original polymers are rather hydrophobic as highlighted but contain acidic functional groups. Increased exposure to AP improved the water wetting of the treated surfaces because of the formation of a variety of oxygen and nitrogen containing functions. The morphology and pore structure was assessed using SEM and a liquid displacement test. The PLGA and PS foam samples have central regions which are open porous interconnected networks with maximum pore diameters of 49 μm for PLGA and 73 μm for PS foams. (Figure Presented) © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

Reliability of fibre Bragg gratings in polymer optical fibre

In this paper we report on investigations of some of the factors that have a bearing on the reliability and repeatability of polymer fibre Bragg gratings. The main issues discussed are the fibre preform composition, the fibre drawing conditions and the thermal history of the fibre grating.