Crosstalk-optimized multicore fiber true time delay lines

We demonstrate the feasibility of implementing 2D sampled discrete true time delay lines built upon crosstalk-optimized heterogeneous multicore fibers. By properly designing the trench-assisted refractive-index profile of each individual core, we assure a crosstalk performance that is insensitive to fiber curvatures for bending radii higher than 158 mm. For regions above that threshold radius, a worst-case intercore crosstalk around -100 dB was achieved, a value much lower than the -70 dB previously reported in the literature.