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Showing 1 to 13 of 13 for “"Long Period Grating"”.
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Long Period Grating-Based pH Sensors for Corrosion Monitoring
… health evaluation of the infrastructure. The long period grating (LPG) element is highly sensitive to refractive index changes and with appropriate design geometry a variety of target molecules can be detected. Optical fiber long period gratings are designed to act as spectral loss elements …
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Composite Films for Modifying Evanescent Wave Characteristics in Long-Period Grating Biosensors
… response. Fiber optical immunosensors based on long-period gratings have limited sensitivity at the refractive index of ordinary aqueous solutions (~1.33). A composite film was designed to raise the local refractive index of the sensor, thus increasing sensitivity. Titanium dioxide deposition …
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Design and characterisation of long period grating (LPG) - based optical fibre sensors for acoustic wave detection
… Representing one type of optical fibre sensors, long period gratings (LPGs) have shown a high sensitivity to a number of parameters, including temperature, strain, refractive index and bending, therefore they have been explored widely for a range of potential sensing applications. This thesis is …
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Ionic Self-Assembled Multilayers in a Long Period Grating Sensor for Bacteria and as a Source of Second-Harmonic Generation Plasmonically Enhanced by Silver Nanoprisms
… The sensor was based on a turn-around point long period fiber grating (TAP-LPG). Unlike conventional LPGs, in which the attenuation peaks shift wavelength in response to environmental changes, TAP-LPGs have a highly sensitive single wavelength peak with variable attenuation. ISAMs were …
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Long-Period Gratings as Immuno-Diagnostic biosensors
… refractive index sensitivity of a fiber optic long-period grating. The long period grating couples light from the forward propagating guided core mode of a single-mode fiber into discrete circularly symmetric cladding modes. Due to imperfections in the cladding surface, loss bands are seen in …
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Properties and sensing applications of long-period gratings
A long-period grating is obtained by introducing a periodic refractive index modulation in the core of a hydrogen-sensitized germanosilicate fiber. The phase-matching condition causes light from the fundamental guided mode to couple to discrete, forward-propagating cladding modes. These cladding …
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Fabrication of intensity-based Long-Period-Gratings fiber sensor with CO2 Laser
… technique and procedures for producing long period grating (LPG) fiber sensors with point-by-point irradiation under a CO2 laser beam. The type of fiber sensor under examination is desirable to be highly sensitive to the variation of the thickness and refractive index of a thin film …
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Modelling of optical fibre long-period grafting sensors.
In this thesis a mathematical model of the long-period fibre grating (LPG) sensor has been developed. Numerical simulation of the LPG transmission spectrum behavior is studied when changing the refractive index of the ambient. The attenuation bands are seen to shift to shorter wavelengths as the …
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Corrosion detection using metal coatings on fiber optic sensors
… Fabry-Perot interferometer (AEFPI), and the long period grating (LPG) fiber optic sensor. The corrosion monitoring technique used with the EFPI and AEFPI sensors exploits the ability of a thick coating of metal to maintain strain information in fiber optic strain sensors. The sensors are …
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Writing and characterisation methods for UV-photosensitivity based devices and their applications
… One major scope is the improvement of grating fabrication specifications by introducing new writing techniques and the use of advanced characterisation methods for grating testing. For the first time the polarisation control method for advanced grating fabrication has successfully been …
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Fiber-Optic Sensors for Fully-Distributed Physical, Chemical and Biological Measurement
… sensing technique based on a traveling long-period grating (T-LPG) in a single-mode fiber. The T-LPG is generated by pulsed acoustic waves that propagate along the fiber. When there are changes in the fiber surrounding medium or in the fiber surface coating, induced by various physical, …
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Beiträge zur Dispersionskompensation basierend auf der Modenkonversion in höhere Moden und der Ausbreitung dieser Moden in Lichtwellenleitern
… of a higher order mode (HOM). In this work long-period gratings (LPG) were considered as mode converters (chapter 4) as they can excite selective and nearly lossless a higher order mode. The modeling und calculation of these gratings, based on the fiber calculation of chapter 3, is presented …
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Periodic Mesoporous Organosilica: Preparation Characterization and Applications of Novel Materials
… catalysis, sensing or selective adsorption. Periodic mesoporous organosilicas (PMOs) represent an interesting class of hybrid silica materials because of the wide variety of bridging organic groups which can be incorporated within the precursors [(OR)3Si-R-Si(OR)3] giving rise to materials …