Integrated orbital angular momentum mode sorters on vortex fibers

Area of Science:

• Optoelectronics and Optical Communications
• Photonics and Integrated Optics

Background:

• Multimode fibers can guide multiple light modes, offering higher data capacity.
• Vortex modes, characterized by orbital angular momentum (OAM), are promising for advanced optical communication.
• Efficiently sorting and routing these modes is crucial for practical applications.

Purpose of the Study:

• To design, fabricate, and characterize integrated mode sorters for multimode fibers guiding vortex modes.
• To demonstrate a compact and robust device for sorting multiple OAM modes.
• To enable widespread exploitation of OAM for space division multiplexed optical communication.

Main Methods:

• Utilized 3D direct laser printing to fabricate a collimator and a Cartesian to log-polar mode transformer.
• Integrated these components onto the tip of vortex fibers.
• Characterized the performance of the mode sorters with two types of fibers, sorting four or eight modes.

Main Results:

• Successfully designed and fabricated polarization-insensitive integrated mode sorters.
• Demonstrated the ability to sort different vortex modes into distinct exit angles.
• Achieved compact and robust sorting of either four or eight different modes.

Conclusions:

• The integrated mode sorters are effective for separating vortex modes in multimode fibers.
• This technology facilitates space division multiplexing for enhanced optical communication.
• Integration of vortex fibers and multiplexers paves the way for practical OAM-based data multiplexing.