Increasing sensitivity of arc-induced long-period gratings—pushing the fabrication technique toward its limits

Abstract

This paper presents an investigation of the sensing properties of long-period gratings (LPGs) written with the electric-arc technique in commonly used standard germanium-doped Corning SMF28 and boron co-doped Fibercore PS1250/1500 fibers. In order to increase the sensitivity of the LPGs, we studied and established for each fiber the writing parameters allowing for the coupling of the highest possible order of cladding modes at a resonance wavelength around λ = 1550 nm. The sensitivity of the LPGs to refractive index, to temperature and to hydrostatic pressure was investigated. The experimental results were supported by extensive numerical simulations. Thanks to the well-established and precisely controlled arc-writing process, we were able to reduce the minimum period of the gratings down to 345 and 221 μm, respectively, for LPGs based on the SMF28 and PS1250/1500 fibers. To the best of our knowledge, these are the shortest periods ever achieved for these fibers using the arc-manufacturing technique. The pressure sensitivities of 13 and 220 pm bar −1 are the highest ever measured for LPGs written in the SMF28 and PS1250/1500 fibers, respectively. Moreover, a reduction in the diameters of the SMF28 fiber induced by the arc was found, which significantly affected the distribution of resonances generated by the coupled cladding modes.

Opto-Electrochemical Sensing Device Based on Long-Period Grating Coated with Boron-Doped Diamond Thin Film

“…Fabrication procedure of LPGs with computer-assisted precision arc-discharge apparatus has been described previously in [15]. In this stage of the experiment, we used Corning SMF28 fiber samples to write gratings with period of Λ = 500 µm.…”

Pressure sensitivity of dual resonant long-period gratings written in boron co-doped optical fiber

“…In our previous works we have reported the significant sensitivity of LPGs written with a cost-effective electric arc method in standard germanium-containing single-mode fiber (Corning SMF28) 5 , pure fused silica endless single-mode photonic crystal fiber (PCF ESM-12-01) 6 and germanium and boron (B/Ge) co-doped photosensitive fiber (Fibercore PS 1250/1500) 7 . The sensitivity of the structures was as high as 13 and 220 pm/bar for the SMF28 and PS 1250/1500 fibers, respectively 8 . The LPGs written in boron co-doped fiber show the highest pressure sensitivity reported to date in the literature.…”

Comparative Study of Long-Period Gratings Written in Standard and Fluorine-Doped Fibers by Electric Arc Discharge

“…The main limitation of the EAD-based technique is the difficulty in the fabrication of grating with low pitch. In 2011, Smietana et al reported on the fabrication of a LPG in SMF28 fiber with period of 345 µm, whereas a grating with period of 221 µm was demonstrated in an unconventional fiber (boron co-doped fiber, which is more sensitive to the temperature generated by the arc than the standard fiber) [34]. More recently, the same group demonstrated that LPGs with period lower than 200 μm could be realized only in boron co-doped fibers and with a grating length greater than 50 mm [35].…”