Faster-than-c signals, special relativity, and causality.
Stefano Liberati, Sebastiano Sonego, Matt Visser.
This would be very difficult to achieve. Then instead I suggest Casimir plate wall separation on the order of an atomic diameter of an angstrom, 10-10 m. With the quantum tunneling walls being at 1 nm to 3 nm thick, the Casimir regions would be 1/10th to 1/30th as wide. Then if quantum tunnelling is indeed (near)instantaneous, even if the light speed in the Casimir regions is at standard c, the transmission time for the entire length of the fiber will be 1/10th to 1/30th that of the standard light speed value.
Finally, one of the benefits of quantum mechanics when it was first proposed was that it returned the concept of free will to human existence since Newtonian physics was completely deterministic.
If the predictions and observations of QM can be explained by just superluminal speeds then we are back at the possibility the universe is deterministic.