A dual-Brillouin-peak optical fiber for simultaneous distributed strain and temperature measurement

Single mode (SM) optical fiber with multiple Brillouin scattering peaks can be used for simultaneous strain and temperature measurement based on Brillouin frequency shift (BFS), but the measurement uncertainties are high due to the low Brillouin gains of higher-order acoustic modes. A new SM fiber is designed and fabricated with enhanced Brillouin gain of higher-order acoustic modes so that the gains of the multiple Brillouin peaks are at a similar level. The temperature coefficients of the BFSs of the peaks are also made significantly different to improve the accuracy of the measured strain and temperature.