We present simulations of integrated optical devices based on nanometer-thin metallic stripes or wires suitable for
guiding long-range surface plasmon polaritons at telecom wavelengths. Propagation of light in these circuits can be
directly controlled by using the metal wires simultaneously as waveguides and heating elements. We will show examples
of how resistive heating of metallic waveguides can be used to control confinement or used to affect selected parts of
multi-mode waveguides in order to realize modulation, attenuation and/or switching.