Femtosecond laser fabrication of long period fiber gratings by a transversal-scanning inscription method and the research of its orientational bending characteristics

Abstract In order to make the whole fiber core modified, an improved point-by-point inscription method (called a transversal-scanning inscription method) is proposed to fabricate long period fiber gratings (LPFGs) by using femtosecond laser. LPFGs with an attenuation depth of 16 dB are achieved within the wavelength range of 1580–1680 nm. We have compared the bending properties of LPFGs fabricated by the line-by-line scanning inscription method and the transversal-scanning inscription method at the orthogonal directions. It is found that increasing scanning area using the transversal-scanning method can enhance the bend sensitivity obviously. The resulting curvature sensitivities are −4.82 nm/m −1 and −1.63 nm/m −1 at the 0° and 90° bend orientations respectively, within the curvature range from 1.75 m −1 to 3 m −1 in the experiment. The LPFG-I fabricated by the line-by-line scanning inscription method experiences red-shift, while the LPFG-II fabricated by the transversal-scanning inscription method experiences blue-shift.

[1]  Sumei Wang,et al.  Femtosecond laser fabrication of long period fiber gratings and applications in refractive index sensing , 2011 .

[2]  Gia-Wei Chern,et al.  Corrugated long-period fiber gratings as strain, torsion, and bending sensors , 2001 .

[3]  Young-Geun Han,et al.  Bending sensitivity of long-period fiber gratings inscribed in holey fibers depending on an axial rotation angle. , 2007, Optics express.

[4]  Christian Ban,et al.  Absence of UV-induced stress in Bragg gratings recorded by high-intensity 264 nm laser pulses in a hydrogenated standard telecom fiber. , 2007, Optics express.

[5]  Ian Bennion,et al.  Strong long-period fiber gratings recorded at 352 nm. , 2005, Optics letters.

[6]  F. el-Diasty.  Multiple-beam interferometric determination of Poisson's ratio and strain distribution profiles along the cross section of bent single-mode optical fibers. , 2000, Applied optics.

[7]  K. Chah,et al.  Femtosecond-laser-induced highly birefringent Bragg gratings in standard optical fiber. , 2013, Optics letters.

[8]  Ian Bennion,et al.  Line-by-Line Fiber Bragg Grating Made by Femtosecond Laser , 2010, IEEE Photonics Technology Letters.

[9]  David J. Webb,et al.  Long period gratings written into a photonic crystal fibre by a femtosecond laser as directional bend sensors , 2008 .

[10]  I. Bennion,et al.  Optical bend sensor based on measurement of resonance mode splitting of long-period fiber grating , 2000, IEEE Photonics Technology Letters.

[11]  S. James,et al.  Optical fibre long-period grating sensors: characteristics and application , 2003 .

[12]  Ying Wang,et al.  Structural long period gratings made by drilling micro-holes in photonic crystal fibers with a femtosecond infrared laser. , 2010, Optics express.

[13]  Yuehua Wu,et al.  All-Fiber Curvature Sensor Based on Multimode Interference , 2011, IEEE Photonics Technology Letters.

[14]  Ali Rostami,et al.  Comparative study between LPFG- and FBG-based bending sensors , 2014 .

[15]  Lingyun Xiong,et al.  Directional Bend Sensor Based on Re-Grown Tilted Fiber Bragg Grating , 2010, Journal of Lightwave Technology.

[16]  I. Bennion,et al.  Bending characteristics of fiber long-period gratings with cladding index modified by femtosecond laser , 2006, Journal of Lightwave Technology.

[17]  John E. Sipe,et al.  Long-period fiber gratings as band-rejection filters , 1995 .

[19]  Xin Wang,et al.  A high-sensitive fiber curvature sensor using twin core fiber-based filter , 2014 .

[20]  Shujing Liu,et al.  Sensing Characteristics of Femtosecond Laser-Induced Long Period Gratings by Filling Cladding Holes in Photonic Crystal Fiber , 2014, Journal of Lightwave Technology.

[21]  Yinian Zhu,et al.  Effect of macro-bending on resonant wavelength and intensity of long-period gratings in photonic crystal fiber. , 2007, Optics express.

[22]  J. Albert,et al.  Compact fiber-optic vector inclinometer. , 2010, Optics letters.