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

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 LP01x, LP01y, LP11x and LP11y 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.