Silicon-integrated dual-mode fiber-to-chip edge coupler for 2 × 100 Gbps/lambda MDM optical interconnection

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Silicon Photonics

Background:

• Efficient fiber-to-chip coupling is crucial for high-bandwidth optical communication systems.
• Existing methods often struggle with simultaneously coupling multiple modes from few-mode fibers (FMF) to silicon waveguides.
• CMOS-compatible fabrication processes are highly desirable for scalable photonic integrated circuits.

Purpose of the Study:

• To design and fabricate a silicon-integrated edge coupler capable of dual-mode fiber-to-chip coupling.
• To achieve simultaneous excitation of both LP01 and LP11 modes from few-mode fiber (FMF) into silicon waveguides.
• To demonstrate the functionality of the edge coupler for high-speed optical data transmission.

Main Methods:

• Design of a low-complexity edge coupler comprising a multimode interference section and a triple-tip inverse taper.
• Fabrication on a 220-nm-thick silicon-on-insulator (SOI) wafer using standard CMOS-compatible processes.
• Characterization of the edge coupler's performance in coupling both LP01 and LP11 modes from FMF to silicon waveguides.

Main Results:

• Successful design and fabrication of the silicon-integrated dual-mode edge coupler.
• Demonstration of simultaneous coupling of both LP01 and LP11 modes from FMF to silicon waveguides.
• Successful implementation of a 2x100 Gbps/lambda Pulse Amplitude Modulation (PAM4) multimode interface using the dual-mode fiber.

Conclusions:

• The proposed silicon edge coupler offers a low-complexity and CMOS-compatible solution for dual-mode fiber-to-chip coupling.
• The design supports broadband wavelength division multiplexing and can be scaled for multi-polarization mode coupling.
• This advancement enables high-capacity optical interconnects for future communication networks.