| 摘要 |
A waveguide structure (20, 25, 28) is provided for use in a sensor (100) in which a measurement of the position of an illuminating beam (30) relative to an array (24) of input apertures (21) is to be determined. The waveguide structure comprises a set of optical fibres (20) providing connection between an array of waveguide inputs (21), each waveguide input associated with a respective input aperture of the sensor, and a first set of waveguide outputs (A, B, C) wherein the number of waveguide outputs is less than the number of waveguide inputs, the fibres connecting each waveguide input to a respective unique combination of waveguide outputs such that transmission to the first set of waveguide outputs responsive to illumination of any one of the waveguide inputs defines a respective unique binary pattern of illuminated and non- illuminated waveguide outputs. The binary patterns are representative of aligned measurement positions in the sensor corresponding to the alignment of the illuminating beam with one of the input apertures, and the respective binary patterns corresponding to each pair of adjacent waveguide inputs differ by a single binary digit. |
