Abstract

Guided-wave optical devices are important for serial high-speed processing, particularly when information enters or exits in optical format. Optical logic gates permit "intelligence" or decision-making capability to be introduced into optical transmission or network systems. We show numerically that an all-optical, cascadable, low-energy, soliton logic gate with a fan-out of 2.7 and an energy contrast of 5.5 can be made in a moderately birefringent erbium-doped fiber amplifier (EDFA) that is one soliton period long. The switching results from large frequency shifts associated with cross-phase modulation, birefringent walk-off and 8dB of bandwidth-limited gain. For sub-picosecond pulses and EDFA's with a zero dispersion wavelength between 1.4 and 1.5 microns, one soliton period corresponds to between 5 and 20m of fiber. In contrast, typical nonlinear optical loop mirrors [1] or soliton-dragging logic gates [2] use between 300m and several kilometers of fiber to accumulate slowly a phase or timing shift, resulting in a latency of at least several microseconds and a sensitivity to environmental changes.

© 1993 Optical Society of America