Multiple Breakup of Higher-Order Spatial Solitons

The breakup of high-order spatial solitons propagating in an AlGaAs slab waveguide is studied. We experimentally observe the breakup of such beams into multiple fragments and identify the mechanism of this breakup as the combined effect of two- and three-photon-absorption. We show that the multiple breakup persists even when the value of two-photon-absorption is reduced by an order of magnitude owing to the high value of three-photon-absorption of AlGaAs at the half band-gap. The experimental results extend known mechanism of soliton breakup induced by two-photon-absorption and agree well with numerical beam propagation simulations.