Real-Time Bidirectional 235.2-Tb/s S+C+L Band Transmission Over 10.9-km AR-HCF With 1200/800 Gb/s/ λ

the extremely low Rayleigh backscattering and ultralow loss characteristics of the hollow core fiber, we experimentally demonstrate a real-time same wavelength bidirectional transmission system over a 10.9-km nested anti-resonant nodeless fiber (NANF) link, which achieves a bidirectional net capacity of 235.2 Tbit/s using commercial real-time coherent optical transceivers. The system used a fully loaded S+C+L band WDM configuration over 19.65-THz spectrum, with 131 channels on a 150 GHz grid (51 in S-band, 40 in C-band, and 40 in L-band), resulting in 262 simultaneously transmitted channels bidirectionally. We deployed commercial optical modules across the operating bands, using 800 G modules in the S and L bands and a hybrid of 1.2 T and 800 G modules for the conventional and extended C band, respectively. The successful real-time operation of all channels within the BER requirement validates hollow-core fiber as a viable platform for wideband, same-wavelength bidirectional transmission, underscoring its potential for next-generation ultra-high-capacity optical interconnects.