A chemical active medium on the base of Belousov-Zhabotinsky (BZ)
medium was used to design a "chemical diode". This system, similar to a
semiconductor diode, shows unidirectional propagation of chemical pulses
and may be possible to be used to construct a massively parallel
computational medium. The system of two mesoporous glass plates with
ferroin loaded at the surface was covered by BZ solution and maintained
propagating excitation waves. The unidirectional propagation was
observed when the plates were places so that the corner of the one plate
was close to the plane side of the other plate. The study shows that the
important feature of the system is the geometrical arrangement of the
plates and the gap distance between them. Computer simulations confirm
the experimental results.