Programmable multilayer diffractive optical elements

Although the technology of fixed optical interconnects has shown rapid progress, the programmability requirements remain a difficulty that has not yet been definitively solved. A new configuration of diffractive optical elements is presented that takes full advantage of the progress made in the field of fixed elements and also offers the possibility of programmability. The idea consists of serially combining a few elementary diffractive elements that might be spatially separated. One or some of these elements should be programmable. Configurations that make use of the assets of fixed elements are proposed that overcome the limitations, such as low resolution, that are associated with programmable elements. For illustration, an experiment is described.