A novel temperature-insensitive long-period fiber grating using a boron-codoped-germanosilicate-core fiber

Shima, K.; Himeno, K.; Sakai, Tetsuya; Okude, Satoshi; Wada, Atsushi; Yamauchi, R.

doi:10.1109/ofc.1997.719952

Cited by 49 publications

(32 citation statements)

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“…The improvement of RI sensor sensitivity was also demonstrated by applying sol-gel coating on an LPG [20] or introducing an LPG-based Mach-Zehnder interferometer with a taper in between [21], etc. In the case that the thermal effect has to be eliminated, one can utilize an FBG and LPG hybrid sensor configuration [22], sandwiched long-period grating structure [23], or LPG made in boron-codoped germanosilicate fiber with specific concentration [24]. One of the limitations of LPG sensors that has not been adequately addressed is the transmission-mode operation of LPG, which is not desirable for many practical sensing applications.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective  fiber end-face mirror

Meng¹,

Zhang²,

Wang³

et al. 2009

Opt. Express

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A long-period grating (LPG) based compact optical fiber sensor working in reflection mode is demonstrated. A technique to make a mirror on the cladding region of a fiber end-face to reflect only the cladding modes was realized by growing a polymeric microtip on the core region of the fiber end-face, by photopolymerization, followed by coating the fiber end-face with an aluminum film. Using the cladding-mode-selective fiber end-face mirror, the transmission spectrum of the LPG was "inverted" and reflected. Preliminary results of using the sensor to measure the refractive index of glycerol/water solutions were successfully demonstrated.

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Section: Introductionmentioning

confidence: 99%

Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective  fiber end-face mirror

Meng¹,

Zhang²,

Wang³

et al. 2009

Opt. Express

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“…On the other hand, the presence of B has the reverse effect to that of Ge, where a small reduction in n by adding B also leads to a small reduction in ξ at lower temperatures [16]. Generally, the magnitude of the change in n adding B is much less than Ge.…”

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confidence: 99%

Temperature and strain characterization of regenerated gratings

et al. 2013

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Received Month X, XXXX; revised Month X, XXXX; accepted Month X, XXXX; posted Month X, XXXX (Doc. ID XXXXX); published Month X, XXXX Both temperature and strain characterization of seed and regenerated gratings with and without post-annealing is reported. The high temperature regeneration has significant impact to thermal characterization and mechanical strength of gratings whilst the post annealing has little effect. The observed difference is evidence of viscoelastic changes in glass structure.OCIS Codes: 060.3735, 060.2310Codes: 060.3735, 060. , 060.2370 , and used to measure exhaust temperatures from diesel train turbines [7]. In this letter, the temperature and strain properties of regenerated gratings are characterized. Regeneration involves a greater physical contribution through structural relaxation at areas where stresses are altered in the presence of hydrogen, which simply by being present acts to reduce tensile stresses across the core and cladding and between processed regions -a recent review reveals new insight in this regard [8]. The local relaxation differs between areas of high and low laser exposure during fabrication of the seed grating. Hydride and hydroxyl formation helps to accentuate this difference, which leads to stronger grating writing as well as altering stresses [9], and therefore local pressures, periodically.Bragg gratings were inscribed in B-codoped germanosilicate fiber ([GeO2] ~ 33 mol%; [B2O3] ~ 12 mol %) by direct writing through a 10mm optical phase mask using an ArF laser (λ = 193 nm; pulse fluence: fpulse = 95 mJ/cm 2 ; cumulative fluence fcum = 113 J/cm 2 ; RR = 30 Hz; pulse duration τw = 15 ns).Before grating writing, the fiber was hydrogen (H2) loaded (T = 80 °C , P = 180 bar, t = 4 days), avoiding type In formation [10]. For regeneration, two groups of seed gratings were fabricated -Group (1): regenerated gratings, and Group (2): regenerated gratings subjected to post-annealing at 1100 °C. The typical initial spectra with both reflection, R, and transmission, Tr, of the seed gratings are shown in Fig. 1. A high-temperature heater was used for annealing the gratings and temperature monitored with a type K thermocouple. The thermal processing recipe is shown in Fig. 2 along with the grating reflection strengths (normalized to the initial seed grating). The temperature rose to T = 850 °C over t = 60 min before dwelling for t = 40 min. Over this period, the grating decays completely before regenerating and saturating at a peak reflection. At the beginning of the thermal process, a growth in the reflectivity is observed indicating an annealing out of a negative contribution, possibly arising from stress, early on has occurred, reminiscent of behavior observed with type In (type IIA) formation and annealing. For Group (2) gratings, additional annealing (T = 1100 °C, t = 20 min) was undertaken to stabilise the regeneration process for even higher temperature operation, shown in Fig. 2. The strength of the grating decays further before stabilizing. Fig.1 shows the final spec...

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“…The sensitivity of LPGs to temperature is influenced by the period of the LPG governed by the order of the cladding mode to which coupling takes place (Bhatia 1999) and by the composition of the optical fibre (Shima 1997). The origin of the temperature sensitivity may be understood by differentiating equation (1) (Bhatia et al 1997) …”

Section: Resultsmentioning

confidence: 99%

Design and development of long-period grating sensors for temperature monitoring

Chaubey

Joshi

Kumar

et al. 2007

Sadhana

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Long Period Gratings (LPGs) have been developed using carbon dioxide laser in a standard optical fibre. LPGs with a periodicity of 600 μm and grating length of 24 mm have been inscribed on standard single mode fibre. Such gratings have been used in designing temperature sensors and temperature is monitored up to 80 • C. The sensitivity of such type of sensor is 0·06 nm/ • C where as for standard Fibre Bragg Grating (FBG) it is 0·011 nm/ • C. The LPG performance is also evaluated after γ -ray irradiation for total dose of 5 KGy and has not shown any effect on transmission spectrum.

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A novel temperature-insensitive long-period fiber grating using a boron-codoped-germanosilicate-core fiber

Cited by 49 publications

References 1 publication

Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective  fiber end-face mirror

Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective  fiber end-face mirror

Temperature and strain characterization of regenerated gratings

Design and development of long-period grating sensors for temperature monitoring

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A novel temperature-insensitive long-period fiber grating using a boron-codoped-germanosilicate-core fiber

Cited by 49 publications

References 1 publication

Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective fiber end-face mirror

Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective fiber end-face mirror

Temperature and strain characterization of regenerated gratings

Design and development of long-period grating sensors for temperature monitoring

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Product

Resources

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Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective  fiber end-face mirror

Fabrication of a compact reflective long-period grating sensor with a cladding-mode-selective  fiber end-face mirror