Graphene-based fine-tunable optical delay line for optical beamforming in phased-array antennas.

The design of an integrated graphene-based fine-tunable optical delay line on silicon nitride for optical beamforming in phased-array antennas is reported. A high value of the optical delay time (τ=920  ps) together with a compact footprint (4.15  mm) and optical loss <27  dB make this device particularly suitable for highly efficient steering in active phased-array antennas.