Polymer waveguide phase modulators integrated with silicon nitride waveguides for optical phased array LiDAR beam scanner

Polymer waveguide optical phased array (OPA) beam scanners can achieve stable beam steering with low driving power owing to the large TO coefficient and low thermal conductivity of the polymer material. However, polymeric OPAs with low refractive index contrast exhibit narrow field-of-view (FOV) because of the wide pitch of the output waveguide channels compared to their counterparts of Si and silicon nitride (SiN) photonic integrated circuit platforms. Meanwhile, SiN waveguides offer stronger mode confinement with smaller waveguide core sizes than polymer waveguides, and they can handle high optical power without nonlinear effects. Through monolithic integration of polymer and SiN waveguides using adiabatic transition tapers, a high-performance phase modulator (PM) is achieved for the purpose of demonstrating an OPA device with low power consumption, wide scanning angle, and fast response.