Long period gratings as solution concentration sensors

Falciai, R.; Mignani, A. G.; Vannini, Andrea

doi:10.1016/s0925-4005(00)00714-0

Cited by 147 publications

(67 citation statements)

References 4 publications

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“…1, forms the basis of a suite of sensors using LPGs, for example as a RI sensor [9], a chemical concentration sensor [10], a biochemical sensor [11], [12], a liquid level sensor and for tuneable spectral filters for various industrial production quality control [13]- [15]. These applications, however, are mostly limited by the requirement that the external RI needs to be smaller than that of the cladding.…”

Section: A Long Period Gratings For Sensing Applicationsmentioning

confidence: 99%

Analysis of the Characteristics of PVA-Coated LPG-Based Sensors to Coating Thickness and Changes in the External Refractive Index

et al. 2013

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-Recent research has shown that the transmission spectrum of a long period grating (LPG) written into an optical fiber is sensitive to the thickness and the refractive index (RI) of a thin layer deposited on it, a concept which forms the basis of a number of optical fiber sensors. The research reported herein is focused, in particular, on sensors of this type to create a design with an optimized thickness of the deposited layers of polyvinyl alcohol (PVA) on LPGs forming the basis of a highly sensitive probe. In creating such sensors, the dip-coating technique is used to minimize deleterious effects in the attenuation bands resulting from the inhomogeneity of the coated surface. In this paper, LPGs with different coating thicknesses are uniformly coated with thin layers of PVA and submerged in oils of known RI over the range from 1.30 to 1.70, to create effective RI probes. It is observed that when the coating thickness reaches a particular value that enables a substantial redistribution of the optical power within the overlay, a maximum sensitivity of the sensor can be achieved, even when the overlay has a RI higher than that of the cladding. Permanent repository link

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Section: A Long Period Gratings For Sensing Applicationsmentioning

confidence: 99%

Analysis of the Characteristics of PVA-Coated LPG-Based Sensors to Coating Thickness and Changes in the External Refractive Index

et al. 2013

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“…In optical communication systems, LPGs are applied as gain equalizing filters, wavelength selective devices, band-pass and band rejection filters and wavelength tunable add/drop multiplexers (Vengsarkar et al, 1996a(Vengsarkar et al, , 1996bDong et al, 2009). In the field of sensing systems, they can be applied as structural bend sensors, temperature sensors, axial strain sensors, refractive index sensors and biochemical optical sensors (Patrick et al, 1998a;Bhatia, 1999;Falciai et al, 2001). …”

Section: Introductionmentioning

confidence: 99%

Fibre Sensing System Based on Long-Period Gratings for Monitoring Aqueous Environments

Silva¹,

Coelho²,

Caldas³

et al. 2012

Fiber Optic Sensors

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“…Because the cladding modes suffer from high attenuation, a series of attenuation bands in the fiber transmission spectrum can be seen, each centered at a resonant wavelength that depends on the effective index of the coupled modes and the grating pitch. The resonant wavelength and amplitude of the attenuation bands of an LPFG are very sensitive to perturbations of the external surroundings, and thus LPFGs can be used to measure temperature [11], strain [12], refractive index [13], solution concentration [14], and pH [15]. In recent years a lot of research has focused on high-refractive-index coated LPFGs to enhance the sensor's sensitivity to ambient refractive index changes.…”

Section: Introductionmentioning

confidence: 99%

Research on testing the characteristics of hydrogel film by using a long-period fiber grating

Zhang

Childs

et al. 2009

Appl. Opt.

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A method for testing the physical and optical properties of hydrogel thin films is reported based on using long-period fiber gratings. For humidity levels from 50% to 70% RH, a wavelength decrease of 11:0 nm is observed, with a sensitivity of 0:6 nm=%RH. For humidity levels from 70% to 98% RH, a wavelength increase of 6:3 nm is seen, with a sensitivity of 0:2 nm=%RH. For humidity levels greater than 60% RH, the transmission loss at resonance increases rapidly, showing a high degree of sensitivity of 0:5 dB=%RH. The blueshift of the wavelength was seen to be due to a thickening of the overlay, while the redshift of wavelength is due to the contribution of the drop in refractive index of the overlay. The results match well with what is expected theoretically.

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Long period gratings as solution concentration sensors

Cited by 147 publications

References 4 publications

Analysis of the Characteristics of PVA-Coated LPG-Based Sensors to Coating Thickness and Changes in the External Refractive Index

Analysis of the Characteristics of PVA-Coated LPG-Based Sensors to Coating Thickness and Changes in the External Refractive Index

Fibre Sensing System Based on Long-Period Gratings for Monitoring Aqueous Environments

Research on testing the characteristics of hydrogel film by using a long-period fiber grating

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