  We introduce chip-integrated visible light communication-band modulators
based on niobium (Nb) metallic plasmonic nano-antenna arrays. Our plasmonic
nano-devices provide strong sensitivity to the polarization of the incident
visible light and the geometrical parameters of their subwavelength nanoscale
building blocks. Moreover, they offer optical modulation properties with
modulation depth MD = 60% at resonant wavelength lambda= 716 nm, at room
temperature. By engineering the photo response of the Nb nano-device arrays, we
observe a maximum extinction A(lambda)= 1- R(lambda}) = 95 % at resonant
wavelength {\lambda}= 650 nm. Our results suggest that the integrated Nb
nano-antenna array devices can be considered as suitable platforms for the
realisation of chip-scale optoelectronic devices interfacing cryogenics quantum
circuits, and fibre-based communication systems, for applications in quantum
computing, quantum communication, and quantum processing.
