Two-mode squeezing over deployed fiber coexisting with conventional communications

Squeezed light is a crucial resource for continuous-variable (CV) quantum information science. Distributed multi-mode squeezing critical enabling CV networks and distributed sensing. To date, measured by homodyne detection has been limited to single-room experiments without coexisting classical signals, i.e., on “dark” fiber. Here, after distribution through separate fiber spools (5 km), −0.9 ± 0.1-dB coexistent two-mode measured. Moreover, deployed campus fibers (about 250 m 1.2 −0.5 Prior distribution, the squeezed modes are each frequency multiplexed with several signals—including local oscillator conventional network signals—demonstrating that do not need dedicated dark After joint recorded post-processing using triggered in locations. This demonstration enables future applications sensing rely squeezing.