| 摘要 |
<p>Various optical modulation systems and methods which are based upon modulating the refractive index of a nipi structure. The refractive index modulation is accomplished by applying a controlled voltage differential across the n-doped and p-doped layers of the structure. Staggered contacts to the layers are formed by conductive elements which extend through the structure. One of the elements establishes ohmic contacts with the n layers, and the other with the players. When implemented as an optical spatial phase modulator, one of the nipi contacts is provided as a grid which divides the structure into a matrix of pixel elements, with the other contact comprising separate wires extending through each pixel. A spatial voltage pattern is applied to the pixel wires to inject charge into their corresponding layers, and thereby modulate the refractive indices of the pixels. This imposes a desired spatial phase modulation onto a readout beam transmitted through the nipi structure. Various guided wave applications are also disclosed in which a beam is transmitted through a nipi structure parallel to the n and p layers. The nipi structure is not divided into pixels, but rather has a common voltage differential between its n and p layers. The structure's refractive index is spatially modulated by varying this voltage differential, whereby the spatial voltage modulation is transferred onto the beam.</p> |
