THIN FILM WAVEGUIDE WITH A PERIODICALLY MODULATED NONLINEAR OPTICAL COEFFICIENT

摘要

A phase matched thin film waveguide supportive of electromagnetic wave energy having angular frequencies is disclosed. In one embodiment, the waveguide includes a sequence of strips each of length A/2 in the direction of wave energy propagation and spaced apart from one another a distance A/2, A = 2 pi / DELTA beta , where DELTA beta is the phase constant difference required to satisfy the relationship beta 1 + beta 2 = beta 3 + DELTA beta , beta 1, beta 2 and beta 3 being, to a first order of approximation, the phase constants respectively of the wave energy. In other embodiments, the spaces between the strips are filled with materials whose nonlinear optical coefficient is either zero or different from the nonlinear optical coefficient of the spaced apart strips. The filling material's index of refraction is substantially equal to that of the spaced apart strips.