Ultra-broadband multimode fiber-to-chip edge coupler based on periodically segmented waveguides

Area of Science:

• Photonics and Optical Communications
• Integrated Optics
• Waveguide Technology

Background:

• Mode-division multiplexing (MDM) is crucial for enhancing optical communication capacity.
• Fiber-to-chip MDM interconnects face challenges due to mode mismatch and crosstalk.
• Existing solutions struggle with efficient mode conversion between few-mode fibers (FMF) and few-mode waveguides (FMW).

Purpose of the Study:

• To propose a new multimode coupling solution for MDM systems.
• To achieve efficient mode conversion between FMF and FMW with low refractive index differences.
• To demonstrate low coupling losses for integrated fiber-chip optical interconnects.

Main Methods:

• Utilizing periodically segmented waveguides for multimode coupling.
• Simulating mode conversion between LP modes (FMF) and E modes (FMW).
• Fabricating a device on a polymer platform for experimental validation.

Main Results:

• Simulated coupling losses below 0.90 dB for all modes across 1100-1800 nm.
• Fabricated device achieved low fiber-to-chip coupling losses (<3.0 dB) over a 130 nm bandwidth.
• Demonstrated efficient conversion between LP01, LP11a/b (FMF) and E11, E21, E12 (FMW) modes.

Conclusions:

• The proposed periodically segmented waveguide offers an efficient solution for MDM fiber-chip interconnects.
• This technology enables ultra-efficient integration for future optical communication systems.
• The low coupling losses and broad bandwidth make it a competitive approach for optical interconnections.