Measurements of temperature and strain sensitivities of a two-mode Bragg grating imprinted in a bow-tie fibre

Abstract

A method for measuring the sensitivity of Bragg gratings to external parameters for different spatial and polarization modes is presented together with the results of measurements of sensitivity to temperature and elongation for LPx01, LPy01, LPx11 and LPy11 modes. The difference in response according to the type of mode shows the possibility of performing simultaneous temperature and elongation measurements using two-mode Bragg gratings.

Characteristics of Bragg grating imprinted in highly birefringent side-hole fiber

“…To overcome this difficulty we used a specially developed measurement system shown in Fig. 3a, which was earlier used for characterizing a two-mode Bragg grating imprinted in bow-tie fiber [12]. Transmision spectra of the inv€tigated grating obtained with a standard spectrum analyzer.…”

“…By measuring the location of the center of diffracted peak (for every polarization mode) versus the value of applied parameter, we could determine the grating sensitivity to temperature and pressure for both polarization modes. The numerical method of finding the location of the center of diffracted mode and the calibration procedure of diffracted spectrum were described in our earlier paper [12]. The wavelength resolution obtained in described experiment was equal to 15 pm.…”

“…Recent studies of the Bragg gratings imprinted in birefringent fibers such as panda [9] and bow-tie [10, 1 1] shows that the difference between temperature and strain sensitivities for orthogonally polarized fundamental modes is sufficient to detennine these two parameters by interrogating grating using orthogonally polarized modes. We proved in our last paper [12] that the use of higher order spatial modes LP and LP1 reflected by the two-mode Bragg grating in a bow-tie fiber would be the best solution for simultaneous sensing of temperature and strain. Nevertheless, so for assessing the grating usability for specific application is only possible on experimental basis, after the grating is imprinted in the birefringent host fiber.…”

Effects of distributed birefringence on fiber Bragg grating under non-uniform transverse load

“…The goal of multiparameter sensing with FBG written in Hi-bi fiber has been addressed by several researchers. For example Urbanczyk et al [4] demonstrated a sensor to simultaneously determine temperature and strain sensitivities using a two-mode Bragg grating imprinted in a bow-tie fiber. Guanghui Chen et al [5] described a sensor to simultaneously measure strain and temperature using FBG written in novel Hi-bi optical fiber.…”

Multiparameter Sensor Based on Single High-Order Fiber Bragg Grating Made With IR-Femtosecond Radiation in Single-Mode Fibers

“…In order to avoid the multifiber solution to multiparameter sensing problems, a variety of other alternatives have been used. Techniques to discriminate sensing parameters include double superposed grating structures with different [1], FBGs in fiber with dissimilar diameters [2], utilization of the second-order diffraction from a saturated first-order 1550 nm grating [3], FBGs in birefringent fibers [4], etc. These techniques were developed mainly for the particular case of strain and temperature discrimination.…”