Im. Skinner, WHY VARIATIONAL APPROXIMATION REDUCES SOLITON SWITCHING IN NONLINEAR COUPLERS TO THE CW CASE, Optical and quantum electronics, 27(1), 1995, pp. 49-57
Use of the variational approximation to describe soliton propagation i
n a nonlinear optical coupler is shown formally to reduce the problem
to one with the same form as CW operation of a coupler, albeit with a
different form of nonlinearity.