Axial rotation dependence of resonances in curvedCO
            <sub>2</sub>
            -laser-induced long-period fibre gratings

VanWiggeren, Gregory D.; Gaylord, Thomas K.; Davis, Donald D.; Anemogiannis, E.; Garrett, B.; Braiwish, Mohammad I.; Glytsis, Elias N.

doi:10.1049/el:20001019

Cited by 73 publications

(32 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…IV, the single-side irradiation of the CO 2 laser beam results in an asymmetrical index profile within the cross-section of the achieved gratings. As a result, distinct bend-sensitivity of resonant wavelength are observed while a CO 2 -laser-induced LPFG is bent to different fiber orientations, 106,112,113 as shown in Fig. 16.…”

Section: Bend Sensorsmentioning

confidence: 98%

“…17 and 107-110͒ so that a higher PDL usually are observed in the gratings. 25,63,109 Such asymmetrical mode coupling also results that the responses of the CO 2 -laser-induced LPFGs to the applied bending, 21,106,[111][112][113] twisting, [114][115][116] and transverse loading [117][118][119] depend strongly on the fiber orientations, which is distinct from the gratings written by the UV exposure technique. 7,12-14 Moreover, the asymmetry in the stress distribution of the cladding is found to be much larger than that in the core of the CO 2 -laser-induced LPFG.…”

Section: Asymmetrical Mode Couplingmentioning

confidence: 98%

“…9͑a͒, the laser energy is strongly absorbed on the incident side of the fiber while the CO 2 laser light ͑ = 10.6 m͒ illuminates on the optical fiber. 106 The nonuniform absorption results in an asymmetrical refractive index profile within the cross-section of the CO 2 -laser-induced LPFGs. In other words, a larger refractive index change is induced in the incident side of the fiber than in the opposite side.…”

Section: Asymmetrical Mode Couplingmentioning

confidence: 99%

“…127 To write a grating in an unstressed fiber, a sufficiently high temperature in the core has to be required to relax the residual stress in the core, which demands a high dose of CO 2 laser irradiation because the temperature inside the irradiated fiber decreases rapidly from the surface toward the core. 104,106 To write a grating in a strongly stressed fiber, however, only a sufficiently high temperature on the fiber surface is required to induce viscoelastic strains in the exposed cladding, which can be achieved with a relatively low energy density of CO 2 laser. 29,127 However, Zhang and Chiang 130 recently discovered that the applied tension during the writing process does not always increase the writing efficiency.…”

Section: Applying Prestrainmentioning

confidence: 99%

See 3 more Smart Citations

Review of long period fiber gratings written by CO2 laser

Wang

2010

Journal of Applied Physics

222

134

View full text Add to dashboard Cite

This paper presents a systematic review of long period fiber gratings (LPFGs) written by the CO2 laser irradiation technique. First, various fabrication techniques based on CO2 laser irradiations are demonstrated to write LPFGs in different types of optical fibers such as conventional glass fibers, solid-core photonic crystal fibers, and air-core photonic bandgap fibers. Second, possible mechanisms, e.g., residual stress relaxation, glass structure changes, and physical deformation, of refractive index modulations in the CO2-laser-induced LPFGs are analyzed. Third, asymmetrical mode coupling, resulting from single-side laser irradiation, is discussed to understand unique optical properties of the CO2-laser-induced LPFGs. Fourthly, several pretreament and post-treatment techniques are proposed to enhance the efficiency of grating fabrications. Fifthly, sensing applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based temperature, strain, bend, torsion, pressure, and biochemical sensors. Finally, communication applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based band-rejection filters, gain equalizers, polarizers, and couplers.

show abstract

Section: Bend Sensorsmentioning

confidence: 98%

Section: Asymmetrical Mode Couplingmentioning

confidence: 98%

Section: Asymmetrical Mode Couplingmentioning

confidence: 99%

Section: Applying Prestrainmentioning

confidence: 99%

See 2 more Smart Citations

Review of long period fiber gratings written by CO2 laser

Wang

2010

Journal of Applied Physics

222

134

View full text Add to dashboard Cite

show abstract

“…10 In a separate study, 8 the fraction of absorbed energy in the fiber cladding was calculated with respect to the total absorbed energy (in cladding and in core) at high-intensity 264 nm and 211 nm irradiation. It was shown that with the increase of this fraction from 74.7% (at 264 nm) to 95.5% (at 211 nm) the grating strength increased from 24 to 26 dB.…”

mentioning

confidence: 99%

Strong long-period fiber gratings recorded at 352?nm

et al. 2005

View full text Add to dashboard Cite

We describe long-period grating inscription in hydrogenated telecom fibers by use of high-intensity femtosecond 352 nm laser pulses. We show that this technique allows us to fabricate high-quality 30 dB gratings of 300 m period and 2 cm length by use of a three-photon absorption mechanism. © Long-period fiber gratings (LPFGs, also known as transmission gratings) have existed since the mid-1990s. 1 They were originally fabricated photochemically by UV laser light at wavelengths coinciding with the maximum of the absorption band of defects in germanosilicate glass, and this is the most frequently used way of LPFG fabrication. For this purpose, KrF excimer laser radiation (248 nm; Ref. 2) or the second-harmonic radiation of a cw argon-ion laser (244 nm; Ref. 3) is usually used. Such a conventional low-intensity UV approach leads to a refractive-index change in the Ge-doped fiber core by means of single-quantum photochemical reactions. Recently we used high-intensity 264 nm femtosecond pulses (the fourth harmonic of our Nd:glass laser system 4 ) for recording LPFGs in single-mode telecom fibers. Under these experimental conditions, the inscription proceeds by means of a two-photon mechanism. 5In this report, we applied 352 nm radiation for LPFG inscription in the hydrogenated single-mode telecommunication fibers SMF-28 and SMF-28e. A schematic of the experimental setup is given in Fig. 1. For inscription of LPFGs we used the thirdharmonic radiation of a commercial femtosecond Nd-:glass laser (Twinkle; Light Conversion, Ltd., Lithuania), which was generated in a 2 mm long KDP crystal cut for type I interaction ( = 47.6°, = 45°). The method of frequency tripling was similar to that described in Ref. 6. The pulse duration of the resultant 352 nm pulses was 250 fs (FWHM), the beam diameter was 0.27 cm (FWHM), the repetition rate was 27 Hz, and the pulse energy was as much as 150 J. The femtosecond UV pulses were focused by a CaF 2 spherical lens, with a 48.6 cm focal distance, through a slit of width 150 m and onto a fiber (with the acrylate coating removed) that was placed behind the slit at a distance of ϳ100 m. The movement of the fiber and the control of the light's fluence were accomplished according to the method described in Ref. 5. For LPFG inscription we used the standard telecom fiber SMF-28 (supplied by Elliot Scientific) and the enhanced telecom fiber SMF-28e (supplied by Corning), both with a core diameter of 8.2 m, a cladding diameter of 125 m, and a numerical aperture of 0.14. The fibers were sensitized in a hydrogen atmosphere at 160 bars ͑120 kTorr͒ at 80°C for 90 h.Figures 2(a) and 2(b) present the experimental transmission loss spectra for two recorded gratings in SMF-28 and SMF-28e fibers, respectively. These gratings were fabricated with a 300 m period, and they were 2 cm in length.First we want to emphasize that our LPFGs, inscribed by high-intensity 352 nm pulses, are stronger than those produced by other photochemical methods. This statement refers to gratings of the same length and the sam...

show abstract

CO2-Laser-Inscribed Long Period Fiber Gratings: From Fabrication to Applications

Wang¹,

He²

2019

Handbook of Optical Fibers

View full text Add to dashboard Cite

Axial rotation dependence of resonances in curvedCO ₂ -laser-induced long-period fibre gratings

Cited by 73 publications

References 3 publications

Review of long period fiber gratings written by CO2 laser

Review of long period fiber gratings written by CO2 laser

Strong long-period fiber gratings recorded at 352?nm

CO2-Laser-Inscribed Long Period Fiber Gratings: From Fabrication to Applications

Contact Info

Product

Resources

About

Axial rotation dependence of resonances in curvedCO 2 -laser-induced long-period fibre gratings

Cited by 73 publications

References 3 publications

Review of long period fiber gratings written by CO2 laser

Review of long period fiber gratings written by CO2 laser

Strong long-period fiber gratings recorded at 352?nm

CO2-Laser-Inscribed Long Period Fiber Gratings: From Fabrication to Applications

Contact Info

Product

Resources

About

Axial rotation dependence of resonances in curvedCO ₂ -laser-induced long-period fibre gratings