All-optical Flip-flop Based on SOA and MZI switch

In this paper, a new all optical flip-flop structure based on semiconductor optical amplifier (SOA) and Mach-Zehnder interferometer (MZI) is presented and demonstrated. Through carrying out a detailed analysis of SOA's NPR effect and the coupled SOA-MZI structure, we build up a theoretical SOA model with polarization dependent rate-equations and MZI model employing SOA cross-phase modulation in the scheme. We will implement four kinds of clocked flip-flop, including D-, SR-, T-, and JK-types. Each type has its own logic circuit and working principle. We demonstrate the effectiveness of proposed programs by showing the extinction ratio and state switching speed. The state switching speed includes the rising and falling edges triggering times. In the experiment, to facilitate analysis, the clock pulse repetition frequency is 1 GHz, the rising edge transition time can decrease to less than 50 ps and the extinction ratio is about 30 dB.