Cost-effective multimode polymer waveguides for high-speed on-board optical interconnects

Cost-effective multimode polymer waveguides, suitable for use in high-speed on-board optical interconnections, are presented. The fundamental light transmission properties of the fabricated waveguides are studied under different launch conditions and in the presence of input misalignments. Low loss (∼0.04 dB/cm at 850 nm) and low crosstalk (< -30 dB) performance, relaxed alignment tolerances ±20 μm) and high-speed operation at a 10-Gb/s data rate are achieved. No degradation in the high-speed link performance is observed when offset input launches are employed. Moreover, a range of useful waveguide components that add functionality and enable complex on-board topologies are presented. The optical transmission characteristics of the fabricated components are investigated and it is shown that excellent performance is achieved. Excess losses as low as 0.01 dB per waveguide crossing, the lowest reported value for such components, and bending losses below 1 dB for 90-degree and S-shaped bends are obtained even with multimode fiber launches. Moreover, high-uniformity power splitting and low-loss signal combining are achieved with Y-shaped splitter/combiners while a variable splitting ratio between 30%-75% is demonstrated with the use of multimode couplers. Overall, the devices presented are attractive potential candidates for use in on-board optical links.