High-performance optical phased array for LiDARs demonstrated by monolithic integration of polymer and SiN waveguides.

Optical phased array (OPA) beam scanners for light detection and ranging (LiDAR) are proposed by integrating polymer waveguides with superior thermo-optic effect and silicon nitride (SiN) waveguides exhibiting strong modal confinement along with high optical power capacity. A low connection loss of only 0.15 dB between the polymer and SiN waveguides was achieved in this work, enabling a low-loss OPA device.

Monolithic integration of polymer waveguide phase modulators with silicon nitride waveguides using adiabatic transition tapers.

Polymer waveguide phase modulators (PMs) demonstrate high thermal confinement with outstanding thermo-optic properties and can provide stable low-power phase modulation in optical phased arrays (OPA). On the other hand, silicon nitride (SiN) waveguides produce stronger optical confinement with smaller waveguide core sizes than polymer waveguides and can handle high optical power without nonlinear effects. In this work, a high-performance PM was achieved by monolithic integration of a polymer waveguide and tapered SiN input and output waveguides.

Frequency Response of Thermo-Optic Phase Modulators Based on Fluorinated Polyimide Polymer Waveguide.

Polymer waveguide phase modulators exhibit stable low-power phase modulation owing to their exceptional thermal confinement and high thermo-optic effect, and thus, have the merit of thermal isolation between channels, which is crucial for an optical phased array (OPA) beam scanner device. In this work, a waveguide phase modulator was designed and fabricated based on a high-refractive-index fluorinated polyimide. The propagation loss of the polyimide waveguide and the temporal response of the phase modulator were characterized.

Fast-running beamforming algorithm for optical phased array beam scanners comprised of polymeric waveguide devices.

The phase error imposed in optical phased arrays (OPAs) for beam scanning LiDAR is unavoidable due to minute dimensional fluctuations that occur during the waveguide manufacturing process. To compensate for the phase error, in this study, a fast-running beamforming algorithm is developed based on the rotating element vector method. The proposed algorithm is highly suitable for OPA devices comprised of polymer waveguides, where thermal crosstalk between phase modulators is suppressed effectively, allowing for each phase modulator to be controlled independently.

Compact solid-state optical phased array beam scanners based on polymeric photonic integrated circuits.

Optical phased array (OPA) devices are being actively investigated to develop compact solid-state beam scanners, which are essential in fields such as LiDAR, free-space optical links, biophotonics, etc. Based on the unique nature of perfluorinated polymers, we propose a polymer waveguide OPA with the advantages of low driving power and high optical throughput. Unlike silicon photonic OPAs, the polymer OPAs enable sustainable phase distribution control during beam scanning, which reduces the burden of beamforming.