  We study nonlinear modes of dual-core photonic crystal fiber couplers made of
a material with the focusing Kerr nonlinearity. We find numerically the
profiles of symmetric, antisymmetric, and asymmetric nonlinear modes, and
analyze all-optical switching based on instability of the symmetric mode. We
also describe elliptic spatial solitons controlled by the waveguide boundaries.

Pattern Formation and Solitons