Numerical analysis of an all-optical logic XOR gate based on an active MZ interferometer

Summary form only given. A vital issue for practical implementation of optical XOR gates is the tolerance of the gate towards imperfect synchronism of the two signals participating in the XOR operation, as well as the tolerance towards variations of the signal pulse widths. These issues are investigated numerically for a Mach-Zehnder interferometer (MZI) based XOR gate. For bit-rates up to 40 Gb/s, the synchronization tolerance of a MZI XOR gate is determined by the pulse width for RZ format. For the NRZ format, the tolerance decreases as the rise/fall-time approaches the timeslot. The gate is found to be very tolerant towards differences in the RZ pulse width.