Intermodal interferometer for strain and temperature sensing fabricated in birefringent boron doped microstructured fiber.

We present a compact in-line fiber interferometric sensor fabricated in a boron doped two-mode highly birefringent microstructured fiber using a CO(2) laser. The intermodal interference arises at the fiber output due to coupling between the fundamental and the first order modes occurring at two fiber tapers distant by a few millimeters. The visibility of intermodal interference fringes is modulated by a polarimetric differential signal and varies in response to measurand changes. The proposed interferometer was tested for measurements of the strain and temperature, respectively, in the range of 20-700 °C and 0-17 mstrain. The sensitivity coefficients corresponding to fringe displacement and contrast variations are equal respectively for strain -2.51 nm/mstrain and -0.0256 1/mstrain and for temperature 16.7 pm/°C and 5.74×10(-5) 1/°C. This allows for simultaneous measurements of the two parameters by interrogation of the visibility and the displacement of interference fringes.

[1]  Hwa-Yaw Tam,et al.  High pressure sensor based on photonic crystal fiber for downhole application , 2010 .

[2]  Hugo Thienpont,et al.  Polarizing photonic crystal fiber with low index inclusion in the core , 2010 .

[3]  A. Bjarklev,et al.  Gas sensing using air-guiding photonic bandgap fibers , 2004, Conference on Lasers and Electro-Optics, 2004. (CLEO)..

[4]  Byeong Ha Lee,et al.  Ultracompact in-line broadband Mach-Zehnder interferometer using a composite leaky hollow-optical-fiber waveguide. , 2008, Optics letters.

[5]  Gonçal Badenes,et al.  Highly Sensitive Sensors Based on Photonic Crystal Fiber Modal Interferometers , 2009, J. Sensors.

[6]  Joel Villatoro,et al.  Holey fiber tapers with resonance transmission for high-resolution refractive index sensing. , 2005, Optics express.

[7]  Petr Hlubina.  White-light spectral interferometry to measure intermodal dispersion in two-mode elliptical-core optical fibres , 2003 .

[8]  John M. Fini,et al.  Microstructure fibres for optical sensing in gases and liquids , 2004 .

[9]  Valerio Pruneri,et al.  Simple all-microstructured-optical-fiber interferometer built via fusion splicing. , 2007, Optics express.

[10]  Joel Villatoro,et al.  Fast detection of hydrogen with nano fiber tapers coated with ultra thin palladium layers. , 2005, Optics express.

[11]  J. Villatoro,et al.  Temperature-independent strain sensor made from tapered holey optical fiber. , 2006, Optics letters.

[12]  H. Choi,et al.  All-fiber Mach-Zehnder type interferometers formed in photonic crystal fiber. , 2007, Optics express.

[13]  O. Frazao,et al.  Temperature-Independent Strain Sensor Based on a Hi-Bi Photonic Crystal Fiber Loop Mirror , 2007, IEEE Sensors Journal.

[14]  Krassimir Panajotov,et al.  Comparison of different methods for rigorous modeling of photonic crystal fibers. , 2006, Optics express.

[15]  Orlando Frazão,et al.  Optical sensing with photonic crystal fibers , 2008 .

[16]  David J. Richardson,et al.  Sensing with microstructured optical fibres , 2001 .

[17]  Hwa-Yaw Tam,et al.  Temperature-insensitive strain sensor with polarization-maintaining photonic crystal fiber based Sagnac interferometer , 2007 .

[18]  Tadeusz Martynkien,et al.  Measurements of modal birefringence and polarimetric sensitivity of the birefringent holey fiber to hydrostatic pressure and strain , 2004 .

[19]  Hanne Ludvigsen,et al.  Surface-plasmon-resonance sensor based on three-hole microstructured optical fiber. , 2008, Optics express.

[20]  Vittoria Finazzi,et al.  Temperature-insensitive photonic crystal fiber interferometer for absolute strain sensing , 2007 .