Improved optical vector matrix multipliers are disclosed. The multipliers comprise: a plurality of light sources, each operable to radiate light of intensity ui; fan-out optics arranged to expand the light radiated by the light sources in one dimension; a spatial light modulator comprising a plurality of light modulating zones, each zone receiving light from one of the light sources and being operable to modulate the intensity of said received light by a factor of vij; and fan-in optics arranged to focus the modulated light onto a plurality of light detectors. The fan out optics, spatial light modulator, and fan-in optics are arranged such that an intensity of light proportional to ∑ i ⁢ ⁢ u i ⁢ v ij is received at each light detector; and the fan-out optics comprise guided-wave optical components. Specific embodiments are disclosed in which the fanout optics comprise optical splitters, or a partially guiding wedge prism.