Dylan Renaud
As a PhD candidate in applied physics at Harvard’s Kenneth C. Griffin Graduate School of Arts and Sciences and the John A. Paulson School of Engineering and Applied Sciences, 2024 Harvard Horizons Scholar Dylan Renaud has developed new technologies that respond to the critical need for quicker, more sustainable data transmission. His Horizons project, “Nanoscale Photonics: The Power of Tiny Devices for Solving the World’s Largest Challenges,” combines research on how light interacts with very small objects with practical computing applications to create novel devices that move information via light. This hardware, Renaud says, will be crucial as the amount of data in the world continues to rapidly expand.
Renaud has developed short-wavelength integrated photonic circuits in thin-film lithium niobate that contain features as much as a hundred times smaller than the thickness of human hair. “These tiny devices allow us to route light inside them,” he says, “and also interact very energy-efficiently with that light to do things like change its color or turn it on and off very quickly. Those kinds of operations are foundational to the way that we send information around the world today.”
There are distinct advantages to using light as an information carrier when it comes to transferring data between points on a computer network. One of the most important is signal loss. When information is moved from one place to another using an electric current, for instance, that current interacts with the transmitting material in ways that significantly weaken the signal. Light, however, only weakly experiences transmission loss.
Though Renaud draws on the general advantages of using light as an information carrier, his specific contributions to the field have involved designing and manufacturing small-scale modulators, devices that manipulate properties of light such as its phase or intensity. Smaller and demonstrably more power-efficient than conventional technologies, Renaud’s devices can help address the rapidly increasing usage of data––and its associated material, energy, and environmental costs.
The applications of Renaud’s technology are not just limited to impacting modern-day data infrastructure; the ability to control light’s properties energy-efficiently and with very little loss of signal is also important for enabling next-generation technologies. Quantum computing approaches that rely on photons—quanta of light—can benefit from Renaud’s devices, for example, since the ability to control a photon’s properties with little loss of signal is crucial for scaling up the technologies.
As tech startups increasingly focus on integrated photonic circuits for communications, data centers, and new technologies, Renaud says he is hopeful that his work will have a real-world impact.
“We can do measurements in the lab and see that our device is nominally more efficient than what is currently used in the real world,” he says. “But at the end of the day, none of that matters unless our technology is actually used. These devices could offer solutions to some of the world’s biggest challenges.”