Heterogeneous Double Period Array Multicore Fiber and Its Application in Bragg Grating Sensor

A novel heterogeneous double period array multicore fiber (DPAMCF) is proposed, in which the spacing between two adjacent cores is approximately equal and the core sizes change periodically. The modes in the DPAMCF form two supermode groups, which can be attributed to double period distribution of heterogeneous cores. Two supermode groups are phase mismatched and the coupling crosstalk between them is suppressed. Fiber Bragg gratings (FBGs) are successfully inscribed in the DPAMCF and the responses of each grating to the axial strain and temperature are measured. The proposed DPAMCF offers a platform to integrate a series of FBG units with two sets of different Bragg wavelengths into a plane at the same longitudinal position.