Abstract: A new optical diode is disclosed that permits unidirectional transmission of light, the direction of transmission depending on the direction of incidence. The diode comprises a stack of alternating layers of a low-index material and a high-index material. The layers are arranged within the stack such that there is spatial anisotropy of optical pathlengths in the stack and at least the low-index layers or the high-index layers have an optical nonlinearity, either inherently or by doping. At sufficiently high incident intensifies and appropriate wavelengths, such a diode exhibits partial transmission of input light incident from one direction while reflecting almost totally input light incident from the opposite direction.

Abstract: The present invention utilizes the advantages of a switching regulator, such as, for example, the one shown in the National Semiconductor September 1992 publication, without the addition of additional complex control circuitry to provide a highly efficient controller for controlling the average optical output from a laser diode.