Mode-division multiplexing enabled 2D optical phased array with large scale and wide field of view

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Beam Steering Technologies

Background:

• 2D optical phased arrays (OPAs) traditionally face a trade-off between array scale and field of view (FOV).
• Increasing array size often necessitates larger antenna spacings, which inherently limits the FOV.
• This limitation hinders applications requiring both high resolution and broad spatial coverage.

Purpose of the Study:

• To develop a 2D optical phased array (OPA) architecture that simultaneously achieves large-scale design and wide field of view (FOV).
• To overcome the fundamental limitations of conventional OPAs in beam steering.
• To enable advanced optical communication and sensing systems.

Main Methods:

• Implemented a mode-division multiplexing (MDM) strategy within a 2D OPA.
• Utilized a single waveguide bus to encode routing information via distinct waveguide modes.
• Eliminated dense inter-pixel waveguide pathways to reduce spatial footprint.

Main Results:

• Demonstrated an 11.2° × 11.2° FOV at 1.55 μm wavelength.
• Achieved a scalable array size of 16 × ∞ (theoretically unlimited).
• Simulated maximum insertion loss below 3 dB across the C-band for all radiating pixels.

Conclusions:

• The proposed MDM-based 2D OPA successfully integrates large-scale design with wide FOV capabilities.
• This architecture offers a promising solution for free-space optical communication and LIDAR.
• Further optimization can lead to even larger FOV and array dimensions.