Bidirectional wide-angle waveguide grating antennas with flat-top far-field patterns for optical phased arrays

Area of Science:

• Photonics and Optical Engineering
• Solid-State LiDAR Technology
• Integrated Optics

Background:

• Advanced all solid-state LiDAR requires optical phased arrays (OPAs) with large fields of view.
• Existing waveguide grating antennas (WGAs) face limitations in beam steering range and efficiency.

Purpose of the Study:

• To propose and demonstrate a wide-angle WGA that enhances the field of view for OPAs.
• To reduce chip complexity and power consumption in large-scale OPAs.

Main Methods:

• Utilizing downward radiation from WGAs to double beam steering range.
• Designing a common set of power splitters, phase shifters, and antennas for dual-direction steering.
• Implementing a SiO2/Si3N4 antireflection coating to mitigate interference and power fluctuations.

Main Results:

• Achieved a field of view exceeding 90° in both upward and downward directions.
• Demonstrated balanced emissions with normalized intensity variation within 10% across steering angles.
• Exhibited a flat-top radiation pattern, high emission efficiency, and fabrication error tolerance.

Conclusions:

• The proposed WGA significantly expands the field of view for OPAs.
• The design offers reduced chip complexity and power consumption, suitable for large-scale applications.
• This WGA technology holds strong potential for advanced wide-angle optical phased array LiDAR systems.