Microwave technologies are at the heart of some of the most promising quantum computing technologies today. But at the same time, the microwave domain is the biggest bottleneck for the scalability of these systems. By bridging to the optical domain, where applicable, these disadvantages can be bypassed by using optical interconnects, e.g. for connecting quantum computers together in a cluster through optical fibers. This can boost their scalability dramatically. This can be thought of as analogous to the optical MPI technology used in classical computing clusters.

The Miraex Plattform

Miraex, a Startup founded 2019 in Lausanne, Switzerland, develops RF-photonic devices for interconnecting quantum computers and bridging quantum networks, letting them scale to reach their maximum potential.

The Miraex platform uses nanofabricated RF and optical circuits to guide light into structures where photons of different frequencies interact. These devices can convert single photon signals between microwave and optical frequencies. However, their operation requires a careful design that balances circuit and material losses with coupling strength.

Design refinement with Ansys simulations

To refine the design of initial prototypes for fabrication, the Miraex team decided to rely on Ansys tools and CADFEM know-how: Ansys HFSS was chosen to design and characterize microwave circuit elements, while Ansys Lumerical was used to characterize the corresponding optical waveguides. The data was matched together to find an optimal design.

Identifying the right balance

For optimal performance of quantum interconnects, circuit loss must be balanced with the interaction strength over the length of the device. Ansys Lumerical was used to model optical waveguide modes and extract their propagation velocity, which must match the propagation velocity in the electrical circuits determined by Ansys HFSS. Lumerical also provided information about optical plasmonic loss.

Electrostatic simulations in Ansys Maxwell produced the electric field’s overlap with the optical mode, giving an interaction strength. By performing a parametric sweep over geometry, a suitable balance between optical loss and interaction strength was identified.

Drastic complexity and time reduction

The cross-domain design performance, achieved by concentrating on individual solvers in parallel streams, leads to a drastic reduction in complexity and preparation time.
Furthermore, the extensive Pythonic scripting capabilities of the different Ansys products facilitated efficient data postprocessing and exchange of results. 

These enhancements contribute to achieve a first-time-right design, faster time to market, and the ability to drive innovation within the business landscape.