Towards THz beam steering with integrated phased photomixer arrays

This paper presents the necessary integrated optical building blocks for on-chip, lens-free, spectrally selective, solid-state scanning sensors in THz domain. We demonstrate continuous wave (CW) THz generation up to 2.2 THz by photomixing using antenna-coupled silicon-integrated germanium photodiodes, which reach an optical-to-THz conversion efficiency of about 1% at 100 GHz. Additionally, the feasibility of CW detection up to 600 GHz is shown using modified silicon-integrated photoconductive Ge devices. We show THz beam forming within a small antenna array and address key challenges towards the realization of large quasi-optical THz phased arrays, by demonstrating low-loss (<0.2 dB/cm), low phase error routing and optical beam steering within hybrid Si/SiN optical phased arrays. Finally, we present an antireflection structure enabling lens-free THz beam steering.