Abstract: A beam steering device uses a liquid crystal with an array of back electrodes. Voltages are applied to the array to cause a desired phase distribution across the array, the distribution being selected to steer a beam incident upon the array into a desired direction. Reflective elements are disposed to reflect light incident in the spaces between the electrodes to reduce losses and to smooth the transitions in phase between adjacent electrodes.

Abstract: 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.

Abstract: To operate an optical device comprising an SLM with a two-dimensional array of controllable phase-modulating elements groups of individual phase-modulating elements are delineated, and control data selected from a store for each delineated group of phase-modulating elements. The selected control data are used to generate holograms at each group and one or both of the delineation of the groups and the selection of control data is/are varied. In this way upon illumination of the groups by light beams, light beams emergent from the groups are controllable independently of each other.

Abstract: An optical switch uses a polarisation insensitive spatial light modulator operating by a double pass through a liquid crystal cell. The switch includes two such modulators in a cross bar arrangement. Different embodiments employing techniques for reducing cross talk are described.

Abstract: Apparatus and methods are described for of measuring amplitude and phase variations in a spatially coherent beam of light. A beam of coherent light is made incident upon a spatial array of phase modulating elements displaying a pixellated first phase distribution. In a measuring region of said spatial array, the phase distribution is changed to a new value while retaining the first phase distribution outside the measuring region, for example by flashing a single pixel. The change in intensity resulting from the change in phase distribution is then determined.

Abstract: To operate an optical device comprising an SLM with a two-dimensional array of controllable phase-modulating elements groups of individual phase-modulating elements are delineated, and control data selected from a store for each delineated group of phase-modulating elements. The selected control data are used to generate holograms at each group and one or both of the delineation of the groups and the selection of control data is/are varied. In this way upon illumination of the groups by light beams, light beams emergent from the groups are controllable independently of each other.

Abstract: To operate an optical device comprising an SLM with a two-dimensional array of controllable phase-modulating elements groups of individual phase-modulating elements are delineated, and control data selected from a store for each delineated group of phase-modulating elements. The selected control data are used to generate holograms at each group and one or both of the delineation of the groups and the selection of control data is/are varied. In this way upon illumination of the groups by light beams, light beams emergent from the groups are controllable independently of each other.

Abstract: A beam steering device uses a liquid crystal with an array of back electrodes. Voltages are applied to the array to cause a desired phase distribution across the array, the distribution being selected to steer a beam incident upon the array into a desired direction. Reflective elements are disposed to reflect light incident in the spaces between the electrodes to reduce losses and to smooth the transitions in phase between adjacent electrodes.

Abstract: An optical switch uses two ferroelectric liquid crystal spatial light modulators (10, 11) with an interconnect region in between. The switch uses bulk lenses (2, 8) to focus light from an input fibre array (1) to a first spatial light modulator (10), and from the second spatial light modulator (11) to an output array (9). Each spatial light modulator displays a respective hologram selected from a previously calculated set, to cause a desired switching of light from the input fibre array to the output array.

Abstract: An optical switch uses a polarization insensitive spatial light modulator operating by a double pass through a liquid crystal cell. The switch includes two such modulators in a cross bar arrangement. Different embodiments employing techniques for reducing cross talk are described.

Abstract: An optical switch uses a polarisation insensitive spatial light modulator operation by a double pass through a liquid crystal cell. The switch includes two such modulators in a cross bar arrangement. Different embodiments employing techniques for reducing cross talk are described.

Abstract: An optical fiber has a core, an inner cladding and an outer cladding on. In a first region the inner cladding refractive index has a first value which differs from the core refractive index by about 0.0045. The inner cladding refractive index changes along said fiber from the first value to a second value at a free-space end. The second value matches the core refractive index, so that the effective diameter of the core at the free-space end is that of the core plus the inner cladding. Hence the outer cladding acts to constrain the light in the end region. The spot-size and the V number (normalized frequency) are increased, thereby increasing offset tolerances.

Abstract: To operate an optical device comprising an SLM with a two-dimensional array of controllable phase-modulating elements groups of individual phase-modulating elements are delineated, and control data selected from a store for each delineated group of phase-modulating elements. The selected control data are used to generate holograms at each group and one or both of the delineation of the groups and the selection of control data is/are varied. In this way upon illumination of the groups by light beams, light beams emergent from the groups are controllable independently of each other.

Abstract: A beam steering device uses a liquid crystal with an array of back electrodes. Voltages are applied to the array to cause a desired phase distribution across the array, the distribution being selected to steer a beam incident upon the array into a desired direction. Reflective elements are disposed to reflect light incident in the spaces between the electrodes to reduce losses and to smooth the transitions in phase between adjacent electrodes.

Abstract: An optical fiber (12), which presents a beam expanding feature, has a core, an inner cladding, an outer cladding and a sheath. The inner cladding is doped with a photosensitive material like germanium. By using ultra-violet radiation (16) from a copper laser (18) having a Gaussian energy distribution, a refractive index taper may be created inside the fiber. Therefore the tapered fiber has a larger effective area in the coupling region (20), and insertion losses are reduced.