ABSTRACT
This chapter discusses development trends already predictable for broadband optical data transmission and their possible repercussions on communications systems. Such trends primarily involve the further development of existing direct-detection systems to achieve higher bit rates, the use of optical heterodyne methods, and the introduction of monolithic integrated optoelectronic components. Implementation of the results of the developments is conceivable in public communications systems, not only for long-haul systems, but also within the subscriber sphere. High-rate, single-mode (SM) systems as already discussed are at present mainly conceived for use in long-haul purposes in public communications networks. One essential condition for the use of SM fiber in the subscriber field involves the necessity to overcome existing problems involving splicing and plug connectors. Solutions have, however, been published for SM connectors which operate reliably with beam broadening when low demands are placed on the precision.
