High-directional vortex beam emitter based on Archimedean spiral adiabatic waveguides

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Quantum Optics

Background:

• Integrated devices emitting light beams with orbital angular momentum (OAM) are crucial for diverse applications.
• Existing OAM emitters often face challenges with directivity and mode selectivity.

Purpose of the Study:

• To propose and demonstrate a novel, highly directional silicon photonic vortex beam emitter.
• To achieve selective generation of various OAM modes with high directivity and low divergence.

Main Methods:

• Design and fabrication of a compact emitter integrating a 3-turn Archimedean spiral adiabatic waveguide.
• Incorporation of an angular grating for precise control over OAM generation.
• Experimental characterization of the emitter's performance at different wavelengths.

Main Results:

• Demonstration of a compact silicon photonic device capable of generating highly directional vortex beams.
• Achieved vortex beams with small divergence angles and high directivity.
• Selective generation of various OAM modes at different wavelengths with a side-mode suppression ratio up to 13.6 dB.

Conclusions:

• The proposed Archimedean spiral waveguide integrated with an angular grating offers an effective solution for OAM beam emission.
• This compact emitter provides a promising platform for advanced optical communication and sensing technologies.