Characteristics of hydrogenated fiber Bragg gratings

Liou, Cheng-Jyun; Wang, L. A.; Shih, Ming‐Chang

doi:10.1007/s003390050463

Cited by 20 publications

(14 citation statements)

References 17 publications

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“…During this procedure, the temperature of an active fibre in the chamber is maintained at about 403 K in order to speed up the indiffusion process. The concentration of interstitial molecules in the core of the fibre after staying for some time in the chamber with gas is estimated according to a known diffusion formula [15]. As soon as the equilibrium concentration is reached, the temperature in the chamber is slowly raised to about 873 K. Luminescence characteristics are recorded on heating every 50 °C.…”

Section: Photoluminescence Measurement Techniquementioning

confidence: 99%

Near-infrared luminescence of bismuth in fluorine-doped-core silica fibres

Bazakutsa¹,

Golant²

2015

Opt. Express

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Photoluminescence spectra and decay kinetics of bismuth inclusions in silica optical fibres containing fluorine additive in the core glass are studied in the vicinity of a wavelength of 1420 nm at temperatures of 80-900 K under a continuous wave (CW) and a pulsed diode laser pump at a wavelength of 808 nm. At high fluorine concentration and low temperatures, luminescence decay kinetics becomes essentially bi-exponential, typical lifetimes being 720 and 1200 µs. Hydrogen and deuterium loading at pressures of up to 125 bar leads to a decrease of the steady-state luminescence intensity and lifetime. We attribute this to the appearance of an energy transfer bridge from bismuth clusters to vibrational degrees of freedom of diatomic molecules. It is found that in the presence of H(2) or D(2) molecules experiencing random walking in silica, luminescence decay kinetics stop following a single exponential function even in fluorine-free silica-core fibre, deviation from the single exponent being greater at higher temperatures. The induced quenching rate increases with the increase of temperature as well and is greater for H(2) molecules. All conditions being equal, the equilibrium concentration of hydrogen molecules is greater in heavily fluorinated silica. At temperatures below ~250 K, the presence of dissolved molecules has no effect, which speaks for the primary importance of having rotational degrees of freedom of migrating interstitial diatomic molecules in an excited state for effective quenching of bismuth electronic excitations. It is found that the influence of dissolved deuterium is weaker than that of hydrogen. We attribute this feature to a greater angular momentum of the D(2) molecule and correspondingly smaller energy of the molecule's rotational quantum. The results of the experiments show that bismuth clusters mainly located in voids of the silica network, rather than bismuth point defects, are responsible for near-infrared luminescence.

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Section: Photoluminescence Measurement Techniquementioning

confidence: 99%

Near-infrared luminescence of bismuth in fluorine-doped-core silica fibres

Bazakutsa¹,

Golant²

2015

Opt. Express

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“…The first generation of FBGs have been fabricated using photosensitive fibers [1], having a significant Ge-doping that facilitates the process of FBG inscription, and on standard single-mode fibers (SMFs) by means of H 2 loading [6]. More recently, the possibility to use a femtosecond (fs) laser focused on the fiber core has opened the possibility of inscribing an FBG on several types of fibers [7,8].…”

Section: Introductionmentioning

confidence: 99%

Fiber Bragg Grating (FBG) Sensors in a High-Scattering Optical Fiber Doped with MgO Nanoparticles for Polarization-Dependent Temperature Sensing

et al. 2019

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The characterization of Fiber Bragg Grating (FBG) sensors on a high-scattering fiber, having the core doped with MgO nanoparticles for polarization-dependent temperature sensing is reported. The fiber has a scattering level 37.2 dB higher than a single-mode fiber. FBGs have been inscribed by mean of a near-infrared femtosecond laser and a phase mask, with Bragg wavelength around 1552 nm. The characterization shows a thermal sensitivity of 11.45 pm/°C. A polarization-selective thermal behavior has been obtained, with sensitivity of 11.53 pm/°C for the perpendicular polarization (S) and 11.08 pm/°C for the parallel polarization (P), thus having 4.0% different sensitivity between the two polarizations. The results show the inscription of high-reflectivity FBGs onto a fiber core doped with nanoparticles, with the possibility of having reflectors into a fiber with tailored Rayleigh scattering properties.

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“…The first type is a standard FBG and the other two sensors have been created by specifically treating a FBG in a two-step process. The first step in this process consists of the loading of hydrogen into an optical fiber 8 with 25 bars pressure for 15 days at room temperature. This hydrogen loaded fiber is then exposed to UV light to create the FBG, achieving the formation of hydroxyl groups in the core of the fiber.…”

Section: Sensors Developmentmentioning

confidence: 99%

Optical fiber sensors embedded in concrete for measurement of temperature in a real fire test

et al. 2011

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We present the results of a real fire test using optical fiber sensors embedded in concrete samples. The temperature curve used in this experiment is described in the Spanish/European standard UNE-EN 1363-1 temperature profile for normalized concrete resistance to real fire tests, reaching temperatures of more than 1000 • C inside the fire chamber and up to 600 • C inside the concrete samples. Three types of optical sensors have been embedded in concrete: 1. standard fiber Bragg gratings inscribed in photosensitive germanium-boron co-doped fiber, 2. regenerated fiber Bragg grating (RFGB) inscribed in germanium doped fiber, and 3. RFBG inscribed in germanium-boron co-doped fiber. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Characteristics of hydrogenated fiber Bragg gratings

Cited by 20 publications

References 17 publications

Near-infrared luminescence of bismuth in fluorine-doped-core silica fibres

Near-infrared luminescence of bismuth in fluorine-doped-core silica fibres

Fiber Bragg Grating (FBG) Sensors in a High-Scattering Optical Fiber Doped with MgO Nanoparticles for Polarization-Dependent Temperature Sensing

Optical fiber sensors embedded in concrete for measurement of temperature in a real fire test

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