On homoclinic snaking in optical systems

The existence of localized structures, including so-called cavity solitons, in driven optical systems is discussed. In theory, they should exist only below the threshold of a subcritical modulational instability, but in experiment they often appear spontaneously on parameter variation. The addition of a nonlocal nonlinearity may resolve this discrepancy by tilting the 'snaking' bifurcation diagram characteristic of such problems. (c) 2007 American Institute of Physics.