By T. E. Darcie, AT&T Bell Laboratories
AM-VSB lightwave technology has advanced rapidly to meet the requirements of the CATV industry. This paper discusses the present state and projected progress of the most promising of many evolving technologies. Presently available fiber systems, based on 1.3 11m wavelength DFB lasers, can be implemented today with considerable cost and performance improvements over coaxial cable. These systems offer performance approaching fundamental limits and, with continued modest increases in output power (3 dB), offer opportunities for limited ( 4 way) splitting. Externally-modulated YAG lasers could offer similar capabilities, but have not yet been commercialized. Fiber amplifiers offer a possibility for increasing systems margins to the extent required for large scale (> 16 way) splitting, but serious technical hurdles must be overcome. Implementation of such future possibilities would follow naturally from an established base of today's fiber technology.