Low-latency WDM intensity-modulation and direct-detection transmission over >100km distances in a hollow core fiber

The pervasive digital economy, fueled by developments in datacenter networking and cloud/edge computing, relies ever increasingly on the implementation of short- to metro-range high-capacity, low-latency optical communication links. In this paper, it is demonstrated that the low spectrally flat chromatic dispersion and ultralow nonlinearity possible in hollow-core fibers (HCFs) compared to conventional solid-core fibers offer significant potential for the transmission of intensity-modulation and direct-detection (IM-DD) signals over 100-km-scale distances. Specifically, the longest HCF-only IM-DD wavelength-division multiplexed (WDM) C-band transmission experiments (>100km) without chromatic dispersion compensation to date are reported, achieving reach improvements of approximately 5 times and 2 times compared to using standard single-mode fiber and non-zero dispersion-shifted fiber, respectively, in the same experimental recirculating loop set-up. For >100-km transmission, a significant >150-µs latency reduction can be obtained using HCF. These results, in combination with recent progress in loss reduction in HCFs, indicate that such fibers present a promising route to the realization of simple, cost-effective, high-capacity, ultra-low-latency IM-DD WDM transmission links with the potential to revolutionize optical networks in the years to come.