摘要 |
<p>A passive, all optical communications network is provided in which a single optical source in a central station serves many outstations (e.g. telephones in customers' premises). Time division multiplexed optical signals from a laser source are transmitted along a single optical fibre (14) from a central station (4). The signal is split between several secondary fibers at a first splitter (10) (e.g. array of passive couplers) and between further sets of fibers at a second set of splitters (12). At this stage there are 120 individual fibres to customers' premises (8). Digital speech or data is sent back to the central station by a laser in the customers' premises operating in a low duty-cycle mode. The 120 data streams are interleaved at the branching points.</p> |