Bend-insensitive ultra short long-period gratings by the electric arc method and their applications to harsh environment sensing and communication

Abstract

Ultra short long-period gratings (LPGs) fabricated using the electric arc discharge method are demonstrated with regular single-mode fibers. The gratings were as short as two periods, which were the shortest LPGs ever reported. The evolution of this short gratings and their characteristics are investigated in this paper. The excellent bending insensitivity and high temperature robustness demonstrated by this unique LPG make it particularly suitable for harsh environment sensing and communication.

Ultrashort Long-Period Fiber Grating Sensors Inscribed on a Single Mode Fiber Using CO2 Laser Radiation

“…The two exceptions to this range (and the only ones we found in the literature) are the works of Wang [20] and Nam et al [9]. The first engraves the LPFGs in PCF (Photonic Crystal Fiber) using a CO 2 laser and the second uses electric arc for producing ultrashort LPFGs on regular single mode fibers.…”

“…There are many fabrication techniques inducing a permanent change on the refractive index: laser-based inscription systems such as UV [6], femtosecond pulses [7], and CO 2 laser nearinfrared radiation [8], or physically deforming the fiber using other methods such as electric arc discharges [9][10][11], ion implantation [12], or microbends [13].…”

“…These gratings are fabricated with periods ranging from hundreds of micrometers to millimetres, and the majority have lengths of around 25-40 mm; representative typical examples reported in the literature are summarized in Table 1 [6,7,9,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. The two exceptions to this range (and the only ones we found in the literature) are the works of Wang [20] and Nam et al [9].…”

“…In this paper, we present LPFGs written in single mode fibers (Corning SMF-28) using CO 2 laser radiation (10.6 m wavelength) with the remarkable characteristic of having a 2 Journal of Sensors [20] CO 2 laser 2.8 * * * Rao and Zhu [21] CO 2 laser 30 * * Vengsarkar et al [22] KrF laser 25.4 * * Rao et al [23] CO 2 laser 40 2000 Lan et al [24] CO 2 laser 46 * * Oh et al [25] CO 2 laser 42, 47, 50 * * Li et al [26] fs laser 25.2 436 Han et al [27] UV light 20 400 Zhang et al [28] Laser * * [35] CO 2 laser 27 * * Bhatia [6,36] UV 10 280 Nam et al [9] Electric arc 2 500 Duan et al [7] fs laser 34 570 * Engraved in a PCF (Photonic Crystal Fiber). * * Not specified.…”

Temperature sensing using an optical time domain reflectometer and mechanical long-period fiber gratings fabricated from a heat-shrinkable tube

“…LPFGs have been extensively investigated for use in optical communication and sensing applications because of their sensitivity to strain, temperature, and refractive index [1,2,3]. Numerous techniques are available for fabricating LPFGs.…”