An entirely passive all-optical device, referred to as an optical hard
limiter, includes alternating layers of materials having oppositely
signed Kerr coefficients and substantially different linear indices of
refraction, wherein the higher linear index material has the negative
Kerr coefficient and the lower index material has the positive Kerr
coefficient. The optical device has two distinct transmittance curves.
Various optical devices and systems can be built from such optical hard
limiters.