Nonlinear wave propagation in an asymmetric converging Y junction

Nonlinear wave propagation in an asymmetric converging Y junction, which consists of a nonlinear cladding, a linear film, and a linear substrate, is studied. The nonlinear dispersion curves of the successive sections of the Y junction are calculated to be used to illustrate the evolutions of the eigenmodes. The field incident from the nonlinear thinner branch can evolve into the symmetric mode of the stem with a high coupling efficiency. An insertion coupler for a time-multiplexed loop is suggested. Recently nonlinear waveguide junctions have been investigated extensively for their interesting switch-ing behavior. The self-switching transition changes sharply with its intensity. ' Furthermore the wave-guide X junction is shown to exhibit the capability of switching a light beam by controlling the intensity of another light beam or the relative phase between these two light beams.2 The studies have led to a growing interest in all-optical switching based on waveguide junctions.3 Here we use the nonlinea