Ultra-broadband mode multiplexers based on three-dimensional asymmetric waveguide branches

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Mode-division multiplexing (MDM) is crucial for increasing optical fiber communication capacity.
• Existing mode multiplexer designs often face challenges with crosstalk, polarization dependence, and fabrication complexity.

Purpose of the Study:

• To propose and demonstrate a novel three-dimensional (3D) waveguide mode multiplexer structure.
• To achieve efficient multiplexing and demultiplexing of optical modes for ultra-broadband communication.

Main Methods:

• Designing a 3D waveguide structure based on adiabatic mode transitions in multilayer asymmetric waveguide branches.
• Fabricating three-mode and four-mode multiplexers using polymer materials.
• Characterizing device performance, including modal crosstalk, polarization dependence, and insertion loss.

Main Results:

• Demonstrated a 3D waveguide mode multiplexer with low modal crosstalk (<-10 dB).
• Achieved negligible polarization dependence and low fiber connection loss.
• Validated operation over the C+L band and beyond.

Conclusions:

• The proposed 3D waveguide mode multiplexer structure is effective for multi-mode operation.
• These devices are suitable for ultra-broadband mode-division multiplexing applications using few-mode fibers.
• The design offers a promising solution for next-generation optical communication systems.