Waveguide. Scanning electron micrograph of a waveguide (bottom left to top right) 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 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.