Despite the benefits that optics and photonics have brought to improving communications, there remains a lack of commercialized optical computing devices and systems, which reduces the benefits of using light as an information-carrying medium. We are developing architectures and designs of photonic logic gates for creating larger-scale functional photonic logic circuits. In contrast to other approaches, we are focusing on the development of logic devices which can be cascaded in arbitrary ways to allow for more complex photonic integrated circuit design. Additionally, optical computing often uses on-off keying, which fails to take advantage of denser encoding schemes often used to optically transmit data. We propose that devices that operate on phase-shift keying will not only be more efficient, but easier to cascade. To achieve the goal of cascadable devices operating on phase-shift keying, we have designed a plasmonic waveguide logic device using inverse design tools. These tools have allowed us to create a device with an arbitrary topology that has increased performance and reduced footprint compared to a conventional device with the same operation. In addition, inverse design simplifies the process of designing devices that operate with phase-shift keying, which can become complicated with conventional design methods. In order to implement inverse design tools for plasmonic devices and phase-shift keying, we used fully 3D FDTD simulations. We compare the inverse-designed devices to more conventional devices in order to characterize their performance.
Krishna Narayan, Mark C. Harrison, "Implementing inverse design tools for plasmonic digital logic devices", Proc. SPIE 11680, Physics and Simulation of Optoelectronic Devices XXIX, 1168005 (5 March 2021); https://doi.org/10.1117/12.2577895
Society of Photo‑Optical Instrumentation Engineers (SPIE)