The paper motivates the need for optical memories that can be directly controlled in the optical domain to avoid energy- and latency-intensive conversions (optical-to-electrical and electrical-to-optical) and data movement inherent to electronic storage in optical processing systems. The authors note that, despite significant advances in integrated photonics for communications and computation, memory has largely remained electronic.
They explicitly state that achieving a scalable optical memory with optical control has been an open problem. In response, the paper proposes and demonstrates a set–reset (SR) latch implemented using universal optical logic gates based on micro-ring modulators, aiming to address this challenge within programmable silicon photonics. The explicit open problem they identify frames the historical gap the work seeks to fill.
