Abstract: In some examples, a controller for a network includes a path computation module that determines, for a plurality of LSPs or other flows having a common source, shortest paths of the network from the common source to respective destinations of the plurality of LSPs based at least on a minimum bandwidth. The path computation module further determines, after determining the shortest paths, a shortest path for the LSP of the plurality of LSPs as the shortest path of the shortest paths of the network from the common source to a destination for the LSP. A path provisioning module of the controller, after the path computation module determines the shortest path for the LSP and in response to the path computation modules routing the LSP to the shortest path for the LSP on a network model of the network, installs the LSP to the network as routed to the shortest path.

Abstract: An optical grating includes a sequence of grating lines, the sequence being such that each grating line is centered on a position which is an integer multiple of a line spacing distance from a datum position on the grating, the sequence of grating lines is non-periodic and the sequence of the grating lines is formed from N concatenated sub-sequences. Each sub-sequence includes a series of one or more instances of a respective grating line pattern. Such an optical grating has a structure that is more amenable to calculation of the grating lines necessary to achieve a desired characteristic. A method of calculating and fabricating such a grating is also disclosed.

Abstract: A device, particularly an antenna device, for emitting a beam of optical radiation to irradiate a remote target area includes an optical source having a limited wavelength band, and a hologram pattern positioned in the path of a light beam originating from the source, the pattern being selected to produce a composite beam having a predetermined shape or far field pattern conforming to the target area and/or a predetermined distribution of light intensity in the target area. Where the optical source is a point source, the hologram pattern selectively retards the phase of respective components of the incident wavefront to produce a composite beam having a far field pattern that precludes focusing of the beam into a single small spot. The device has particular application in a telecommunication system wherein a data signal is transmitted through free space by an optical beam, at least one characteristic of the beam being controlled by the hologram pattern in the path of the beam.

Abstract: An optical grating includes a sequence of grating lines, the sequence being such that each grating line is centered on a position which is an integer multiple of a line spacing distance from a datum position on the grating, the sequence of grating lines is non-periodic and the sequence of grating lines is formed from N concatenated subsequences. Each subsequence includes a series of one or more instances of a respective grating line pattern. Such an optical grating has a structure that is more amenable to calculation of the grating lines necessary to achieve a desired characteristic. A method of calculating and fabricating such a grating is also disclosed.