Materials-Based Solution Accelerates Photonic Computing

Researchers at the University of Central Florida (UCF) have introduced a previously undescribed class of topological insulators that could lead to more power efficient photonic circuits in a demonstration that is poised to advance quantum computing.

The UCF design diverges from traditional design approaches that introduce topological phases by using tailored, discrete coupling protocols or helical lattice motions. To improve the robustness of the topological features, the UCF team instead used connective chains with periodically modulated onsite potentials. It developed a phase structure to host multiple nontrivial topological phases associated with both Chern-type and anomalous chiral states. The team then laser-etched the chained, honeycomb lattice design onto silica.

Nodes in the design allowed the researchers to modulate the current without bending or stretching the photonic wires. This in turn allowed greater control over the flow of light — and thus, more control over the information that flows into a photonic circuit.

The researchers confirmed their findings using imaging techniques and numerical simulations. In experiments carried out in photonic waveguide lattices, they discovered a strongly confined helical edge state that, owing to its origin in bulk flat bands, could be set into motion in a topologically protected fashion or halted at will, without compromising its adherence to individual lattice sites.

The topological insulator design, which the researchers call bimorphic, supports longer propagation lengths for information packets because it minimizes power losses. The researchers believe that by providing more control and richer features than traditional modulation techniques, their approach to designing bimorphic topological insulators could help bring light-based computing closer to reality.

“Bimorphic topological insulators introduce a new paradigm shift in the design of photonic circuitry by enabling secure transport of light packets with minimal losses,” researcher Georgios Pyrialakos said.

The UCF-developed photonic material overcomes drawbacks of contemporary topological designs that offer fewer features and less control, while supporting longer propagation lengths for information packets by minimizing power losses. Courtesy of Adobe Stock.

Next steps for the team will include incorporating nonlinear materials into the insulator’s lattice. This step could give the researchers active control of topological regions, allowing them to create custom pathways for light packets, professor Demetrios Christodoulides said.

As the size of photonic circuits continues to shrink, topological insulators could be used to fit more processing power into a single circuit without overheating it. In the future, topological insulators could be used to protect and harness the power of fragile quantum information bits to realize quantum processing power hundreds of millions of times faster than conventional computers.

The research was published in Nature Materials (www.doi.org/10.1038/s41563-022-01238-w).