Quantum phase properties of Kerr couplers

We use the concept of the phase space and the Husimi quasidistribution to s tudy quantum phase properties of the optical fields propagating in Kerr cou plers. Fourier coefficients of the phase distributions are introduced and u tilized to examine their spatial development. The collapses and revivals of the mean photon number oscillations between the two waveguides are due to the bifurcation of the phase-difference probability distribution, which has a twofold symmetry in the interval of collapse.