The transverse mode and frequency of photons are alternative degrees of freedom for encoding classical or quantum information using light—these can be used as dits, or qudit. Applications include high-bandwidth communication and computation technologies such as short- or long-haul optical interconnects, optical neural networks, and quantum communication and computation. However, the design of individual components is challenging because of the individual control necessary for each mode - this is often nontrivial.

To overcome the issues faced when designing and fabricating traditional multimode devices, we will develop inverse design and nanofabrication methods which enable us to demonstrate multimode photonic components with broadband operation, improved fabrication robustness, and compact footprint. Our technology will enable the next generation of large-scale photonic circuits which leverage multimode waveguides to improve the performance of short- or long-haul optical interconnects, optical neural networks and quantum communication and computation applications.