  A systematic method for simulating small-scale quantum circuits by use of
linear optical devices is presented. It relies on the representation of several
quantum bits by a single photon, and on the implementation of universal quantum
gates using simple optical components (beam splitters, phase shifters, etc.).
This suggests that the optical realization of small quantum networks is
reasonable given the present technology in quantum optics, and could be a
useful technique for testing simple quantum algorithms or error-correction
schemes. The optical circuit for quantum teleportation is presented as an
illustration.
