Measurement of Pressure and Temperature Sensitivities of a Bragg Grating Imprinted in a Highly Birefringent Side-Hole Fiber

The sensing characteristics of a Bragg grating imprinted in a specially developed highly birefringent sidehole fiber were investigated in detail. We showed that such a grating has almost identical sensitivities to temperature for both linearly polarized modes LP01x and LP01y (approximately 5.9 pm /K) and significantly different sensitivities to hydrostatic pressure ( -1.93 pm /MPa for LP01x and +5.37 pm /MPa for LP01y mode). The sensitivity differences versus mode polarization are so high that this effect can be employed for simultaneous sensing of temperature and pressure by interrogation of the wavelength shifts at LP01x and LP01y modes. Applying interferometric methods, we also measured the sensitivity of the host side-hole fiber to temperature and hydrostatic pressure for each polarization mode. Our results show that there is good agreement between the normalized sensitivities of the host side-hole fiber and those of the grating for the same polarization modes.