Ultrafast all-optical flip-flop based on passive micro Sagnac waveguide ring with photonic crystal fiber

Ultrafast all-optical flip-flop based on a passive micro Sagnac waveguide ring is studied through theoretical analysis and numerical simulation in this paper. The types of D, R-S, J-K, and T flip-flop are designed by controlling the cross-phase modulation effect of lights in this special microring. The high nonlinearity of the hollow-core photonic crystal fiber is implanted on a chip to shorten the length of the ring and reduce input power. By sensible management, the pulse width ratio of the input and the control signal, problems of pulse narrowing, and residual pedestal at the out port are solved. The parameters affecting the performance of flip-flops are optimized. The results show that the all-optical flip-flops have stable performance, low power consumption, high transmission rate (up to 100  Gb/s), and response time in picosecond order. The small size microwaveguide structure is suitable for photonic integration.