Abstract

Because of the increasing demand for bandwidth in optical networks, all-optical bit-level processing at rates exceeding the current limitations of electronic logic will likely play a crucial role in the development of future networks. In particular, all-optical XOR gates may be useful for a variety of tasks in optical time-division multiplexed (OTDM) networks, such as pattern matching, ¹ header processing, ² ultrahigh speed pseudo-random bit pattern generation, and encryption.³ Previously, semiconductor-based interferometric logic gates have been used to perform XOR of data patterns at rates as high as 20 Gbit/s^4,5 and pseudo-random pattern generation has been shown at rates of 1 Gbit/s.³ However, the ultimate speed of these XOR implementations is limited by gain saturation related to interband carrier dynamics in the semiconductor optical amplifier. For applications where operation at high data rates and high contrast is required and latency is not a constraint, fiber-based switches may be desirable. To the best of our knowledge, all-optical XOR operation on two fully-loaded pseudo-random bit sequences has not been demonstrated for data rates higher than 1 Gbit/s. Such a demonstration is important in order to verify the pattern-independent fidelity of the logic gate for time-varying input patterns on both inputs. Here, we demonstrate all-optical XOR of two fully-loaded pseudo-random binary sequences (PRBS) at rates as high as 40 Gbit/s in a novel all-fiber switch.

© 2002 Optical Society of America