Article

Effect of macro-bending on resonant wavelength and intensity of long-period gratings in photonic crystal fiber

Department of Chemical Engineering & Materials Science, Stevens Institute of Technology, Hoboken, New Jersey, United States
Optics Express (Impact Factor: 3.53). 03/2007; 15(4):1804-10. DOI: 10.1364/OE.15.001804
Source: PubMed

ABSTRACT We report the spectral characteristics of CO(2)-laser inscribed long-period gratings (LPGs) in endlessly single mode photonic crystal fiber (PCF) subject to macro-bending. The coupling modes as a result of bending were studied by examining the shifts of resonant wavelengths, the splits of attenuation bands, and the variation in coupling strength of the transmission spectra. A bending coefficient of ~ 27.9 nm.m was determined in the PCF at 180 degrees rotational orientation relative to the point of laser inscription in the curvature range from 2.6 m(-1) to 3.5 m(-1). Compared with conventional fiber LPGs fabricated using the same method, the PCF-based LPGs possess higher sensitivity both to bending and orientation, making them promising for sensor applications.

Download full-text

Full-text

Available from: Henry Du, Apr 14, 2015
0 Followers
 · 
82 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 (LP<sub>0m</sub>) and asymmetric (LP<sub>1m</sub>) 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<sup>- 1</sup>.
    Journal of Lightwave Technology 10/2010; DOI:10.1109/JLT.2010.2064158 · 2.86 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this letter, we report bending and strain sensitivities of helicoidal long-period fiber gratings fabricated by twisting single-mode fibers during CO<sub>2</sub> laser irradiation. Linear spectral shifts of the resonant wavelengths under the bending and tensile strain were observed with the sensitivities of -11.7 nm/m<sup>-1</sup> and -1.1 pm/muepsiv, respectively. The corresponding transmission power variations at the resonance wavelength were 4.1 dB/m<sup>-1</sup> and 2.2 times 10<sup>-4</sup> dB/muepsiv, respectively. Detailed measurement techniques and sensor applications are discussed.
    IEEE Photonics Technology Letters 10/2009; 21(17-21):1232 - 1234. DOI:10.1109/LPT.2009.2024646 · 2.18 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper discusses the applications of photonic crystal fibers (PCFs) for strain and temperature measurement. Long-period grating sensors and in-fiber modal interferometric sensors are described and compared with their conventional single-mode counterparts. The strain sensitivities of the air-silica PCF sensors are comparable or higher than those implemented in conventional single-mode fibers but the temperature sensitivities of the PCF sensors are much lower.
    Journal of Sensors 01/2009; DOI:10.1155/2009/476267