Silicon Nitride Integrated Optical Beamforming Network for Millimeter Wave Photonics Systems

This work presents the design of a $\mathbf{1x4}$ optical true time delay beamforming network integrated into a Si3N4photonic chip for hybrid millimeter wave/photonic systems. The spectral periodicity of a ring resonator-based tree structure is exploited to provide simultaneously the same delay configuration to different gigabit optical channels, increasing the effective beamforming bandwidth. The free spectral range is fixed to 33.3 GHz to assure the combability with wavelength division multiplexing applications. The simulation results show that the progressive delay between outputs can be continuously tuned from 0 ps to 20 ps. These values assure the operation at 60 GHz band.