| 摘要 |
Optical signals are switched by control optical signals. In one arrangement a proportion of an optical signal (20) output from a fibre (10) is deflected and coupled to one fibre (11) rather than being coupled to another fibre (16). This deflection is achieved if both of two control signal beams (14,15) are/were present to generate a refractive index grating in a photorefractive material (19). In another arrangement the transmittance of a Fabry Perot etalon (33), at which the optical beam ( lambda s 31) is directed, is controlled by the presence/absence of a pump signal ( lambda p 37). Holograms on holographic plates (17,18:32,34) serve to affect (deflect, focus, collimate or reflect) the optical beams as appropriate. The holographic plates and photorefractive material (or etalon) are preferably rigidly disposed in a light-proof container with suitable input and output means for the optical signals. |
