Dual Wavelength Botda for Strain/Temperature Discrimination

The sensitivity of Brillouin Frequency Shift (BFS) to strain and temperature has been studied in a bending-loss insensitive fiber (BIF), at two different wavelengths (850 and 1550, nm). The results show that the ratio between strain sensitivity at the two wavelengths is different from the ratio between temperature sensitivity, which can be conveniently used for simultaneous and distributed measurement of the two parameters using a single sensing element. Experimental results, carried out at 1-m spatial resolution, demonstrate the feasibility of the proposed method.