摘要 |
An optical switch (10) is interposed between two light paths (12,14) comprising optical fibres (20,22) and focusing elements (24,26). The switch includes a toroidal enclosure (28) filled with a transparent fluid 40 and a ferrofluid pellet (30) whose rest position is below the space between the light paths which are coupled through the transparent fluid. Electrical coils (32,34) surround the focusing elements and are energisable to generate a magnetic field to move the ferrofluid pellet to a position between the light paths, in which the opacity of the ferrofluid uncouples the light paths. Additional coils (36,38) may be energised to return the ferrofluid pellet upon de-energisation of the coils (32,34). |