Demonstration of a Cross-Encoded RFI QKD system in a field-deployed multi-core fiber. - Massimo Giacomin; Julian Morales Traktenberg; Matías Rubén Bolaños; Giammarco Di Sciullo; Tetsuya Hayashi; Cristian Antonelli; Giuseppe Vallone; Paolo Villoresi; Costantino Agnesi (OFC, 2026)