Experimental demonstration of an all-optical fiber-based Fredkin gate

We propose and report on what we believe to be the first experimental demonstration of an all-optical fiberbased Fredkin gate for reversible digital logic. The simple 3-input /3-output fiber-based nonlinear optical loop mirror architecture requires only minor alignment for full operation. A short nonlinear element, heavily doped GeO₂ fiber (HDF), allows for a more compact design than typical nonlinear fiber gates. The HDF is ideal for studying reversibility, functioning as a noise-limited medium, as compared to the semiconductor optical amplifier, while allowing for cross-phase modulation, a nondissipative optical interaction. We suggest applications for secure communications, based on "cool" computing.