Beyond Silica Assumptions: Optical Network Design in the Hollow-Core Era

Hollow-core fiber (HCF) is often presented as a modestly improved transmission medium that can be inserted into networks originally designed for solid-core silica.

We argue instead that recent progress -- most notably the reported attenuation below 0.1 dBkm$^{-1}$, together with a broad low-loss window, reduced propagation delay, and extremely low optical nonlinearity -- makes it timely to reconsider which long-standing design conventions are fundamental to optical communication and which are specific to silica fiber.

By reviewing implications at the physical-layer, transceiver, and network-architecture levels, we suggest that the most durable benefits of HCF may arise not from its use as a drop-in replacement, but from cross-layer co-design.

We also outline the studies and experimental demonstrations needed to determine where such advantages are genuinely achievable.