Architectures for Future Multigigabit Lightwave Networks

摘要

Architectures for future fiber optic networks for voice, video and data applications are considered. Broadband Integrated Services Digital Network (B-ISDN) will be introduced for these applications sometime after 1995. B-ISDN will be based on fast switching of rather small (48-byte) packets. The packet switches themselves will probably be electronic and will take advantage of the ability of semiconductor electronic technology to build very complex, regular, repetitive structures. Packet switching provides a flexible, efficient means of sharing bandwidth limited communications resources. Developing fiber optic technology, however, offers another revolutionary alternative, the Passive Optical Network (PON), based on the realization that the inherent bandwidth of the fiber is immense and using optical frequency division multiplexing to exploit this. The PON has significant advantages over centralized packet switching in some applications (particularly video distribution), is simpler, facilitates the addition of new services, can be begun and extended in small increments, and requires much less initial investment in the network. However, the PON depends upon the commercial development of several components, such as tunable lasers and coherent receivers, which have so far been proven only in laboratories.