Traditional electronic devices are limited by speed and efficiency. Advances in ultra-fast optical technologies offer new approaches to address this challenge. The Set-Reset (SR) flip-flop is a fundamental timed logic circuit element that possesses memory and storage capabilities. Current research on optoelectronic SR flip-flops demonstrates that these devices can replicate the fundamental operations of electrical SR flip-flops only when the input signal is electrical and the output signal is optical. Nevertheless, the realization of ultrafast switching between operational states at the femtosecond scale under all-optical operating mode presents a considerable challenge for SR flipflops. In this paper, we present an all-optical SR flip-flop, which enables ultrafast switching among its five states on a femtosecond timescale. This performance is achieved under a specific input time delay, while avoiding the desynchronization issues induced by electrical signal delays. The shortest switching time between different states can be 35 fs. This research realizes femtosecond-level state switching speeds, which can promote the development of ultrafast photonic information processing and ultrafast optical devices.
Li et al. (Fri,) studied this question.