The paper suggests to consider synchronous optical fiber communication network with new digital hierarchy; to fully utilize the installation of optical amplifiers in eliminating the use of regenerative repeater; to encourage the trial applications of densely packed multiple optical carrier systems and coherent communication systems on toll lines

and to accelerate the research on optoelectronic integration technology.The object of all these developments is to fully exploit the huge potential capacity of the optical fiber

as well as to reduce the quantity of hardware components so as to ensure high system reliability.