Terminated polymer waveguide with low coupling loss to single-mode fiber for 100 Gbps optical interconnects and...

Area of Science:

• Photonics and Optical Engineering
• Materials Science for Electronics

Background:

• High-speed optical interconnects are crucial for data centers and high-performance computing.
• Standard single-mode fiber (SSMF) is widely used, but efficient coupling with on-board components remains a challenge.
• Polymer waveguides offer potential for low-cost, high-density optical integration.

Purpose of the Study:

• To design and fabricate polymer waveguides with minimal coupling loss to SSMF.
• To evaluate the performance of these waveguides for high-speed optical interconnects (100 Gbps and beyond).
• To demonstrate the feasibility of using polymer waveguides for advanced data transmission standards like PAM4.

Main Methods:

• Designing polymer waveguides with mode field diameters matched to SSMF.
• Fabricating waveguides on FR-4 substrates.
• Measuring propagation loss, coupling loss, and bit error ratio (BER) for optical transmission.
• Demonstrating single-lane 56 Gbaud (112 Gbps) and 60 Gbaud (120 Gbps) PAM4 transmission.

Main Results:

• Achieved theoretical coupling loss as low as 0.07 dB and fabricated coupling loss below 0.17 dB at 1310 nm.
• Measured propagation loss of 0.32 dB/cm for the fabricated polymer waveguides.
• Successfully demonstrated 112 Gbps and 120 Gbps PAM4 optical transmission with BER below 10^-4.
• Observed power penalty less than 1 dB, indicating robust performance.

Conclusions:

• The fabricated polymer waveguides exhibit excellent low-loss characteristics, compatible with both printed circuit boards and fiber optics.
• The demonstrated high-speed data rates (112 Gbps and 120 Gbps) confirm the potential of these waveguides for next-generation optical interconnects.
• The polymer waveguide technology is a promising solution for single-lane 100 Gbps optical interconnects and future higher-speed applications.