Product: FDTD, MODE, FEEM, and HEAT Application: Quantum Computing
“With the help of Ansys Lumerical with their optimization, scripting, and cloud support, we were able to optimize each and every component of our X8 circuit for unprecedented low-loss performance, compactness, and high manufacturing tolerance.”, Blair Morrison, Lead of Integration at Xanadu
“Ansys Lumerical FDTD solutions paired with its cloud Accelerators allowed us to reduce insertion loss by more than 15% while significantly accelerating our design schedule”, Matteo Menotti, Quantum Photonics Engineer at Xanadu
Xanadu is an innovative startup setting out “to build quantum computers that are useful and available to people everywhere”, pursuing an approach based on programmable integrated quantum photonics. Leveraging the technological advances of the last decades in integrated photonics fabrication and measurement driven by the telecom industry, Xanadu’s solution promises to avoid much of the cumbersome and expensive cryogenics required for superconducting-based solutions in favor of a compact form factor operating at room temperature. An additional benefit to the approach taken by Xanadu is the scalability of the solution, which is enabled by their architectural choices and the use of integrated photonics. Based on these premises, the company recently published their blueprint for a fault-tolerant universal quantum computer .
The primary challenge to building quantum computers is achieving fault tolerance, and the error mitigation strategies used to correct even a single logical qubit can require thousands of physical qubits. For Xanadu, this means that photonic components must be designed with low loss while maintaining performance and stability with respect to manufacturing imperfections. This can only be achieved with savvy component design techniques coupled with the right simulation tools. Minimal loss is crucial and success is tied to efficient optimization workflows centered around simulation tools that are accurate, flexible, and highly parallel. These flows must have the ability to be seamlessly migrated to on-site and cloud-based high performance computing platforms and with high scalability.
Xanadu’s X8 Quantum Computing Chip
Xanadu’s X8 chip was recently launched in the Fall of 2020 and is the first of its kind [2, 3]. X8 is a 4mm x 10mm 8-qubit Gaussian Boson Sampling (GBS) device based on photonics and fabricated using a silicon nitride process. When developing X8, Xanadu considered several simulation solutions but, in the end, decided to use an Ansys multiphysics workflow based on Lumerical FDTD, MODE, FEEM, and HEAT.
The decision to use Ansys Lumerical tools for simulation was driven by their accuracy, flexible scripting support, advanced optimization functions, and highly interoperable multiphysics solvers. Ansys Lumerical provided an ideal platform for Xanadu to achieve their aggressive design goals with a custom flow that combines their internally developed tools with best-in-class photonics simulation.
With an aggressive development timeline, Xanadu leveraged high-performance cloud computing and Lumerical FDTD Accelerators. This was made possible because Ansys Lumerical tools are highly parallelizable and can be seamlessly deployed to both onsite and cloud-based high performance computing platforms.
With the accuracy, flexibility, and cloud-readiness of Ansys Lumerical tools, Xanadu was able to efficiently meet their goals. Xanadu’s lead of integration Blair Morrison states, “with the help of Ansys Lumerical with their optimization, scripting, and cloud support, we were able to optimize each and every component of our X8 circuit for unprecedented low-loss performance, compactness, and high manufacturing tolerance”.
1. Bourassa, J. Eli, et al. “Blueprint for a scalable photonic fault-tolerant quantum computer.” Quantum 5 (2021): 392.
2. Arrazola, J. M., et al. “Quantum circuits with many photons on a programmable nanophotonic chip.” Nature 591 (2021): 54-60.
3. Vaidya, Varun D., et al. “Broadband quadrature-squeezed vacuum and nonclassical photon number correlations from a nanophotonic device.” Science advances 6 (2020): eaba9186