Polymer Optical Waveguides in High-Performance Interconnect Systems

Polymer optical waveguides have emerged as a versatile and cost-effective platform for short-reach data links and board-level interconnects in high-performance electronic systems. Owing to their low fabrication cost, mechanical flexibility and compatibility with standard printed circuit board processes, polymer waveguides offer a scalable route to integrate optical links on and between chips. Both single-mode and multimode formats have been demonstrated, enabling low-loss, high-bandwidth transmission over centimetre- to metre-scale paths. Recent advances in refractive-index tuning, surface smoothness and three-dimensional routing have reduced insertion losses to sub-dB/cm levels while maintaining relaxed alignment tolerances. Moreover, graded-index profiles and novel coupling structures—including 45° mirror couplers and out-of-plane prism couplers—have further enhanced mode matching to glass fibres and silicon photonic chips. Taken together, these developments position polymer waveguides as a practical enabler for high-density optical interconnects in data centres, high-performance computing and on-board photonic networks.

Research from Nature Portfolio

Recent studies have introduced multifunctional polymer waveguide devices that combine data transmission with secure optical encryption. A dual-layer fluorescent polymer waveguide chip has been demonstrated, in which fluorescent oligomers are doped into an epoxy-based SU-8 matrix to form two stacked guiding layers. By modulating the pumping wavelength and pulse-code frequency, the system achieves dynamic encryption of a high-speed data stream, with immediate detection of eavesdropping attempts via selective wavelength switching. This approach illustrates the potential for highly integrated, scalable optical interconnects that simultaneously address bandwidth and security requirements in advanced communication networks.

Research from all publishers

Low-loss, flexible single-mode polymer photonic platforms have reported record attenuation as low as 0.11 dB/cm at 850 nm, using biocompatible commercial polymers and simple fabrication techniques. These free-standing waveguides survive repeated bending to millimetre radii without performance degradation and support passive components such as Y-branches and multi-mode interferometers for on-board signal routing. Furthermore, investigations into roughness-induced scattering loss have clarified the dominant role of sidewall roughness in small-core single-mode waveguides. Experimental measurements and theoretical modelling reveal that sidewall irregularities contribute nine times more loss than top-surface roughness, guiding optimised fabrication for sub-0.3 dB/cm performance. Complementing this, studies of flexible multimode polymer waveguide arrays have characterised bending- and twist-induced excess loss and crosstalk under various launch conditions. These arrays maintain bandwidth-length products exceeding 150 GHz·m and crosstalk below 35 dB around bending radii of 6 mm, demonstrating robust performance for board-level optical backplanes and short-reach links in demanding environments.

Polymer Optical Waveguides in High-Performance Interconnect Systems publication trend

The graph below shows the total number of articles in polymer optical waveguides in high-performance interconnect systems across all publications each year (not limited to Nature Index journals).

Technical terms

Polymer optical waveguide: A light-guiding structure formed in a polymer substrate, typically comprising a higher-index core and lower-index cladding for confining optical modes.

Single-mode waveguide: A waveguide whose core dimensions support the propagation of only the fundamental optical mode, reducing modal dispersion.

Multimode waveguide: A waveguide with core dimensions large enough to support multiple optical modes, allowing relaxed alignment but higher modal dispersion.

Insertion loss: The optical power loss, measured in decibels, experienced when light is coupled into and transmitted through a waveguide link.

Crosstalk: Unwanted coupling of optical power between adjacent waveguides or channels, expressed in decibels.

Graded-index profile: A refractive-index distribution in the waveguide core that varies radially to reduce intermodal dispersion and improve bandwidth.

Pulse-code modulation: A digital modulation technique in which an analogue signal is sampled, quantised and encoded as a sequence of optical pulses for secure transmission.

References

1. Dual-layer optical encryption fluorescent polymer waveguide chip based on optical pulse-code modulation technique. Nature Communications (2023).
2. Low loss, flexible single-mode polymer photonics.. Optics Express (2019).
3. Investigation on roughness-induced scattering loss of small-core polymer waveguides for single-mode optical interconnect applications.. Optics Express (2020).
4. Flexible Multimode Polymer Waveguide Arrays for Versatile High-Speed Short-Reach Communication Links. Journal of Lightwave Technology (2018).
5. Polymer waveguides for electro-optical integration in data centers and high-performance computers. Optics Express (2015).
6. Low-loss light coupling with graded-index core polymer optical waveguides via 45-degree mirrors. Optics Express (2016).
7. Direct laser written polymer waveguides with out of plane couplers for optical chips. APL Photonics (2017).