Cascaded Two-Core PCFs-Based In-Line Fiber Interferometer for Simultaneous Measurement of Strain and Temperature

A new fiber sensor configuration based on the cascaded in-line fiber interferometers has been proposed and experimentally demonstrated for simultaneous measurement of strain and temperature. In order to make the cascaded in-line interferometers, we used two different types of two-core photonic crystal fibers (TCPCFs) having two cores in the symmetry and asymmetry structures. The TCPCFs have different transmission characteristics owing to the distinct geometric structures of the integrated cores, this causes the different strain and temperature sensitivities and thus the two parameters can be discriminated. The measurement resolutions are achieved to be $11.1~\mu \varepsilon $ and 1.10 °C for strain and temperature, respectively, in the 10 pm wavelength resolution.