Characterization of inter-core-crosstalk in tapered multicore optical fibers

We have methodically implemented and measured fiber tapers of different waist lengths and diameters in a seven-core optical fiber to describe and analyze the inter-core crosstalk between all the cores of the fiber. We describe the crosstalk between the central and external cores but also between outer cores, where the distance to the rest of the cores is not uniform. We analyze how the optical spectra evolve as the coupling coefficient and length increase, founding significant differences depending on the taper waist diameter showing that these devices can be used in different applications, from optical sensing to signal processing.