Microphotonics is a branch of technology that deals with directing light on a microscopic scale. It is used in optical networking.
Microphotonics employs at least two different materials with a large differential index of refraction to squeeze the light down to a small size. Generally speaking virtually all of microphotonics relies on Fresnel reflection to guide the light. If the photons reside mainly in the higher index material, the confinement is due to total internal reflection. If the confinement is due many distributed Fresnel reflections, the device is termed a photonic crystal. There are many different types of geometries used in microphotonics including optical waveguides, optical microcavities, and Arrayed Waveguide Gratings.
Photonic crystals are non-conducting materials that reflect various wavelengths of light almost perfectly. Such a crystal can be referred to as a perfect mirror. Other devices employed in microphotonics include micromirrors and photonic wire waveguides. These tools are used to "mold the flow of light", a famous phrase for describing the goal of microphotonics.
Currently microphotonics technology is being developed to replace electronics devices. For instance, the long-standing goal of an all-optical router would eliminate electronic bottlenecks, speeding up the network. Perfect mirrors are being developed for use in fiber optic cables
Light bounces off the small yellow square that MIT physics professor John Joannopoulos is showing off. It looks like a scrap of metal, something a child might pick up as a plaything. But it isn't a toy, and it isn't metal. Made of a few ultrathin layers of non-conducting material, this photonic crystal is the latest in a series of materials that reflect various wavelengths of light almost perfectly. Photonic crystals are on the cutting edge of microphotonics: technologies for directing light on a microscopic scale that will make a major impact on telecommunications.
In the short term, microphotonics could break up the logjam caused by the rocky union of fiber optics and electronic switching in the telecommunications backbone. Photons barreling through the network's optical core run into bottlenecks when they must be converted into the much slower streams of electrons that are handled by electronic switches and routers. To keep up with the Internet's exploding need for bandwidth, technologists want to replace electronic switches with faster, miniature optical devices, a transition that is already under way