Polarization-dependent curvature sensor based on an in-fiber Mach-Zehnder interferometer with a difference arithmetic demodulation method.

A curvature sensor based on a polarization-dependent in-fiber Mach-Zehnder interferometer (MZI) is proposed. The MZI is fabricated by core-offset fusion splicing one section of polarization maintaining fiber (PMF) between two single mode fibers (SMFs). Two independent interference patterns corresponding to the two orthogonal polarization modes for the PMF are obtained. The couple efficiency between the core mode and the cladding mode decreased with the increasing of the bending on the MZI part. The curvature variation on the MZI part can be obtained by detecting the fringe visibility of the interference patterns. A difference arithmetic demodulation method is used to reduce the effects of the light source power fluctuations and temperature cross-sensitivity. Experimental results show that maximal sensitivity of -0.882 dB/m(-1) is obtained under a measurement range of 0.1 to 0.35 m(-1) for the curvature sensor. With the use of difference arithmetic demodulation method, the temperature-curvature cross-sensitivity and light source power fluctuations effects on the proposed sensor are decreased by 94% and 91%, respectively.

[1]  Chi Chiu Chan,et al.  Mach–Zehnder Photonic Crystal Interferometer in Cavity Ring-Down Loop for Curvature Measurement , 2011, IEEE Photonics Technology Letters.

[2]  Zhaobing Tian,et al.  Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators , 2008, IEEE Photonics Technology Letters.

[3]  Bo Dong,et al.  Temperature insensitive curvature measurement with a core-offset polarization maintaining photonic crystal fiber based interferometer , 2011 .

[4]  Wenjun Zhou,et al.  Simultaneous measurement of curvature and temperature based on PCF-based interferometer and fiber Bragg grating , 2011 .

[5]  Perry Ping Shum,et al.  Photonic-crystal-fiber-based Mach–Zehnder interferometer using long-period gratings† , 2006 .

[6]  Peng Zu,et al.  Curvature measurement by using low-birefringence photonic crystal fiber based Sagnac loop , 2010 .

[7]  P. Caldas,et al.  All-fiber Mach-Zehnder curvature sensor based on multimode interference combined with a long-period grating. , 2007, Optics letters.

[8]  Juan Kang,et al.  A highly-birefringent fiber loop mirror temperature sensor demodulation based on a long-period grating in photonic crystal fiber with differential processing , 2012 .

[9]  Tao Zhu,et al.  Refractive index sensing based on Mach-Zehnder interferometer formed by three cascaded single-mode fiber tapers. , 2011, Applied optics.

[10]  O. Frazão,et al.  Simultaneous measurement of curvature and strain using a suspended multicore fiber. , 2011, Optics letters.

[11]  Lecheng Li,et al.  All-fiber Mach-Zehnder interferometers for sensing applications. , 2012, Optics express.

[12]  Xiaoyi Bao,et al.  Double-Pass In-Line Fiber Taper Mach–Zehnder Interferometer Sensor , 2010, IEEE Photonics Technology Letters.

[13]  K. Sooley,et al.  Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature , 2009 .

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

[15]  Xiaoyi Bao,et al.  Application of spectrum differential integration method in an in-line fiber Mach-Zehnder refractive index sensor. , 2010, Optics express.

[16]  A. Martínez-Ríos,et al.  Compact optical fiber curvature sensor based on concatenating two tapers. , 2011, Optics letters.

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

[18]  Tao Zhu,et al.  Highly sensitive bend sensor based on Mach–Zehnder interferometer using photonic crystal fiber , 2011 .

[19]  Tao Wei,et al.  Fiber Inline Core–Cladding-Mode Mach–Zehnder Interferometer Fabricated by Two-Point CO$_{2}$ Laser Irradiations , 2009, IEEE Photonics Technology Letters.