  We introduce continuous supersymmetric transformations to manipulate the
modal content in systems of optical waveguides, providing a systematic method
to design efficient and robust integrated devices such as tapered waveguides,
single-waveguide mode filters, beam splitters and interferometers. These
transformations connect superpartner profiles by smoothly modifying the
transverse index profile along the propagation direction and, if the
modification is performed adiabatically, the transverse electric modes evolve
adapting their shape and propagation constant without being coupled to other
guided or radiated modes. Numerical simulations show that very high fidelities
are obtained for a broad range of devices lengths and light's wavelengths.
