| 摘要 |
A difficulty in optical systems, especially where polarisation-dependent (PD) elements are used, is that the light to be dealt with is subject to fading. To minimise this, the input beam, e.g. from an optical fibre, is applied to a polarisation beam splitter (1), which resolves it into two orthogonally-related beams (2, 3). These are applied to PD elements (4, 5) and therefrom to two detectors (6, 7), or to one detector (6). In an alternative arrangement, only one PD element is used. Such an arrangement, in its "all fibre" version is usable at the input of a node of an optical fibre LAN. <IMAGE> |
