摘要 |
An interferometer (100) for writing Bragg gratings comprising the means for splitting (112) a light beam (114) into two coherent beams (116, 118), and a first optical lens arrangement (106, 108, 110) for bringing the coherent beams to interference for writing the Bragg grating in a photosensitive material (122). The first optical lens arrangement is arraged, in use, to vary an angle beta between the two interfering beams. |