Free-standing microscale photonic lantern spatial mode (De-)multiplexer fabricated using 3D nanoprinting

Area of Science:

• Photonics
• Optical Communications
• Nanotechnology

Background:

• Photonic lanterns (PLs) are crucial for mode division multiplexing (MDM) in high-capacity optical networks.
• Current PL fabrication methods result in large devices, hindering integration with micro-photonic systems.
• 3D micro/nano printing offers a path to fabricating compact, high refractive index contrast photonic structures.

Purpose of the Study:

• To design, fabricate, and characterize a compact photonic lantern for efficient mode conversion.
• To enable the conversion between six single-mode inputs and a single six-mode waveguide.

Main Methods:

• Designed a 6-mode mixing photonic lantern using a genetic algorithm-based inverse design approach.
• Fabricated the device directly on a 7-core fiber using two-photon polymerization 3D printing with a photopolymer.
• Characterized the device for insertion loss, polarization-dependent loss, and mode-dependent loss.

Main Results:

• A 375 µm long photonic lantern was successfully fabricated.
• The device demonstrated low insertion loss of -2.6 dB.
• Measured polarization-dependent loss was -0.2 dB and mode-dependent loss was -4.4 dB.

Conclusions:

• The developed 3D printed photonic lantern offers a compact solution for mode conversion.
• The fabrication technique enables integration with micro-scale photonic systems.
• The device shows promising performance for future optical communication applications.