Optical computation using semiconductor optical amplifiers in cross gain modulation

Summary form only given. The performance of optical networks may be improved by replacing electronics with optics. Computer simulation verifies the feasibility of the proposed scheme. The all-optical logic gates, NOT, NOR, and NOT-XOR were simulated using detailed models and typical parameters for commercial devices for the lasers, SOAs, couplers, and other devices. Results are shown for logic inputs that are two different random bit sequences at optical 2.5 Gb/s (OC48). The bit timing for the signals is aligned. RZ line coded signals are used. The carrier density versus time for the SOA shows a drop when the input signal ones drive the device into saturation. For the NOR gate, nonlinear clipping handles the case where both inputs are one at the same time. The NOT-XOR gate requires coherent operation with one carrier signal out of phase with the other by 180 degrees. Output eye diagrams show the deterioration through the gates in terms of loss/gain, shape degradation, and timing deterioration. Performance optimization is discussed for operation at higher bit rates. The results show that all three gates are feasible and can operate at 2.5 Gb/s or even higher with the approach taken.