Waveguide. Scanning electron micrograph of a waveguide on a microelectromechanical systems (MEMS) device. Waveguides are structures that confine the energy of an electromagnetic wave, for example light, to a narrow path, with no loss of information. The waveguides are the narrow channels in the surface of this silicon chip. MEMS devices are manufactured by using 'micromachining' to etch away parts of the silicon wafer. MEMS technology enables the production of 'smart' products that incorporate microsensors and microactuators. Magnification unknown.