A modular routing node includes a single input port and a plurality of output ports. The modular routing node is arranged to produce a plurality of different deflections and uses small adjustments to compensate for wavelength differences and alignment tolerances in an optical system. An optical device is arranged to receive a multiplex of many optical signals at different wavelengths, to separate the optical signals into at least two groups, and to process at least one of the groups adaptively.

A method for generating three dimensional (3D) displays. The method includes displaying a hologram that combines three (or more) images encoded into three (or more) different OAM channels, and the method also includes reflecting light from the displayed hologram to create a multichannel light beam. Then, the method involves decoding the multichannel light beam to decode and display the three encoded images. The decoding step includes displaying the three encoded images in decoded form in three view zones, three focal planes, or on three spaced-apart planes. The decoding is performed by a single decoding screen using holograms used for generating the three encoded images or is performed by three decoding screens configured based on a differing one of the holograms used for generating the three encoded images. The displaying of the hologram step includes operating a spatial light modulator (SLM) to display the hologram on a screen of the SLM.