The existence of classical analogs for the quantum Fock states is demonstra
ted for the first time. These are the TE modes in a waveguide with a parabo
lic refractive index profile. Since these modes have similar Wigner distrib
ution functions to those of Fock states, it is possible to simulate the pha
se space behavior of quantum Fock states, or of any superposition of them,
by measuring the Wigner distribution function of the corresponding superpos
ition of TE modes.