Fiber-in-the-loop evolution scenarios for B-ISDN and TV/HDTV

The author discusses some of the reasons why additional dark fibers should be installed in the fiber-in-the-loop (FITL) projects to be implemented in the near future to be able to upgrade systems to broadband integrated services digital network (B-ISDN) at a later time. By using various fibers for interactive and distributive services, it becomes possible to develop the technologies for these services independent of each other. One of the benefits of this approach is that it does not impose stringent requirements on the allocation of optical wavelengths. Switched TV, which can only provide a limited number of TV channels on each line, is hampered by the lack of suitable standards and the fact that it is not compatible with consumer equipment. When digital terrestrial TV/HDTV is introduced, suitable receiver interfaces for this new signal format will be developed. The possibility of upgrading to TV/HDTV broadcasting in the asynchronous transfer mode (ATM) format at a later date should be considered at an early stage