Directional Bend Sensor Based on Re-Grown Tilted Fiber Bragg Grating

A novel fiber optic bend sensor is implemented by using a re-grown tilted fiber Bragg grating (TFBG) written in a small core single mode fiber with UV overexposure. The spectrum of the re-grown TFBG contrasts with that of normal TFBG by exhibiting large differences in the amplitude between neighboring symmetric (LP0m) and asymmetric (LP1m) cladding mode resonances, moreover each asymmetric cladding mode resonance splits into two peaks (corresponding to two orthogonal polarization states). The differential response of the three individual resonances of such group provides quantitative information about the magnitude and directions of bends in the TFBG. Numerical simulations indicate that the changes in the cladding-mode profiles in a bent fiber are responsible for this behavior through their impact on coupling coefficients. A bend sensitivity of 0.4 dB. m (for the 18th order group of cladding modes) is experimentally demonstrated within a range of 0-10.6 m- 1.

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

[2]  Hwa-Yaw Tam,et al.  Tilted fiber grating accelerometer incorporating an abrupt biconical taper for cladding to core recoupling. , 2009, Optics express.

[3]  Sheau-Shong Bor,et al.  High-sensitivity temperature-independent differential pressure sensor using fiber Bragg gratings. , 2008, Optics express.

[4]  M.J.F. Digonnet,et al.  Bending-induced birefringence of optical fiber cladding modes , 2006, Journal of Lightwave Technology.

[5]  Aaron R Hawkins,et al.  Surface-relief fiber Bragg gratings for sensing applications. , 2006, Applied optics.

[6]  Jacques Albert,et al.  Intrinsic temperature sensitivity of tilted fiber Bragg grating based surface plasmon resonance sensors. , 2010, Optics express.

[7]  Ian Bennion,et al.  Bend sensors with direction recognition based on long-period gratings written in D-shaped fiber. , 2004, Applied optics.

[8]  I Bennion,et al.  Two-axis bend measurement with Bragg gratings in multicore optical fiber. , 2003, Optics letters.

[9]  Byoungho Lee,et al.  Characteristics of short-period blazed fiber Bragg gratings for use as macro-bending sensors. , 2002, Applied optics.

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

[11]  Kyriacos Kalli,et al.  Formation of type IA fibre Bragg gratings in germanosilicate optical fibre , 2004 .

[12]  Wojtek J. Bock,et al.  Highly sensitive bend sensor with hybrid long-period and tilted fiber Bragg grating , 2010 .

[13]  K S Lee,et al.  Fiber mode coupling in transmissive and reflective tilted fiber gratings. , 2000, Applied optics.

[14]  Bo Liu,et al.  Spectral characteristics and bend response of Bragg gratings inscribed in all-solid bandgap fibers. , 2007, Optics express.

[15]  John E. Sipe,et al.  Tilted fiber phase gratings , 1996 .

[16]  Dietrich Marcuse,et al.  Field deformation and loss caused by curvature of optical fibers , 1976 .

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