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[[File:PhosFos_flexible_skin_demo.jpg|thumbnail|right|400px|Figure 2: Photograph of a real flexible skin with embedded sensors made at the University of Gent]]
The PHOSFOS (Photonic Skins For Optical Sensing) project <ref>http://www.phosfos.eu/</ref> is developing flexible and stretchable foils or skins that integrate optical sensing elements with optical and electrical devices as well as onboard signal processing and wireless communications, as seen in Figure 1. This flexible skins can be wrapped around, embedded in, attached and anchored to irregularly shaped and/or moving objects or bodies and will allow quasi-distributed sensing of mechanical quantities such as deformation, pressure, stress or strain <ref>http://spie.org/x38859.xml?highlight=x2406&ArticleID=x38859</ref>. This approach potentially gives a significant advnatage over conventional sensing systems because of the portablility of the resulting systems and the extended measurement range.
The sensing technology is based around sensing elements called [[Fiber Bragg Grating]]s (FBGs) that are fabricated in standard single core silica fibers, highly birefringent [[Microstructured fiber]]s (MSF) and [[Plastic optical fiber]]s (POF). The silica MSFs are designed to exhibit almost zero temperature sensitivity to cope with the traditional temperature cross-sensitivity issues of conventional fiber sensors. These specialty fibers are being modeled, designed, fabricated within the programme. FBGS written in POF fibers will also be used since these fibers can be stretched up to 300% before breaking. This allows them to be used under conditions that would normally result in catastrophic failure of other types of strain sensors.
[[File:Fabric with embedded POF sensors.jpg|thumbnail|right|400px|Figure 4: Digital image correlation (DIC) image of the strain field in a fabric fitted with polymer optical fiber (POF) and silica gratings under a load of 20N, using dimethyl cyclosiloxane (DMC) and Araldite adhesive. FBG: Fiber Bragg grating. Si: Silicon. N: Newtons. MPa: Megapascals]]
Latest results can be found on the PhosFOS EU webpage [http://www.phosfos.eu/index.php/eng/Phosfos/Conferences-and-Presentations] and include the demonstration of a fully flexible opto-electronic foil <ref>Fully flexible opto-electronic foil, E. Bosman, G. Van Steenberge, I. Milenkov, K. Panajotov, H. Thienpont, J. Bauwelinck, P. Van Daele, Journal of Selected Topics in Quantum Electronics, 2010 </ref>.
Figure 3 shows the [[scattering]] of HeNe [[laser]] light from noise gratings recorded in [[PMMA]] using a 325 nm HeCd laser.
One of the early results from the project was the successful demonstration of a repeatable method of joining the polymer fiber to standard silica fibre. This was a major development and allowed for the first time POF Bragg gratings to be used in real applications outside of the optics lab. One of the first uses for these sensors was in monitoring the strain of tapestries <ref>http://eprints.soton.ac.uk/68650/01/137_Lennard.pdf</ref> shown in Figure 4, <ref>http://spie.org/x39927.xml?ArticleID=x39927</ref>. In this case conventional electrical strain sensors and silica fiber sensors were shown to be strengthening the tapestries in areas where they were fixed. Because the polymer devices are much more flexible they do not distort the material as much and therefore give a much most accurate measurement of the strain in flexible materials. Temperature and humidity sensing using a combined silica / POF fiber sensor has been demonstrated <ref>Optical fibre temperature and humidity sensor, C. Zhang, W. Zhang, D.J. Webb, G.D. Peng, Electronics Letters, 46, 9, pp643-644, 2010, DOI: 10.1049/el.2010.0879 </ref>. Combined strain, temperature and bend sensing has also been shown <ref>Bragg grating in polymer optical fibre for strain, bend and temperature sensing, X. Chen, C. Zhang, D.J Webb, G.-D. Peng , K. Kalli, Measurement Science and Technology, 2010 </ref>. Using a fiber Bragg grating in an eccentric core polymer has been shown to yield a high sensitivity to bend <ref>Highly Sensitive Bend Sensor Based on Bragg Grating in Eccentric Core Polymer Fiber, X. Chen, C. Zhang, D.J. Webb, K. Kalli, G.-D. Peng, A. Argyros, IEEE Sensors Journal, 2010 </ref>.
Other recent progress includes the demonstration of birefringent photonic crystal fibers with zero polarimetric sensitivty to temperature <ref>http://www.phosfos.eu/index.php/eng/Phosfos/Journals/Birefringent-photonic-crystal-fibers-with-zero-polarimetric-sensitivity-to-temperature</ref>, and a successful demonstration of transversal load sensing with fibre Bragg gratings in microstructured optic fibers <ref>http://www.phosfos.eu/index.php/eng/Phosfos/Journals/Transversal-Load-Sensing-with-Fiber-Bragg-Gratings-in-Microstructured-Optical-Fibers</ref>.
==Consortium==
The 2nd "Benefits for Industry" Meeting of the EU FP7 Project PHOSFOS will take place on Sunday 22nd May 2011 in Munich (Germany).
The meeting is co-located with the Industry Meets Academia Workshop organized by SPIE [[http://en.wikipedia.org/wiki/SPIE|SPIE]] as part of the Optical Metrology Conference. It will be followed by the World of Photonics Congress and the Laser World of Photonics Trade Fair in Munich, in the week from 23rd to 26th May 2011.
This Meeting is the second in its kind gathering all companies that have expressed their possible interest in the technology developed by the EU FP7 project PHOSFOS.
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