Fiber-optic communications systems are provided for optical communications networks. Fiber-optic communications links may be provided that use spans of transmission fiber to carry optical data signals on wavelength-division-multiplexing channels at different wavelengths between nodes. An apparatus and method are disclosed to use one optical light source per node to perform OTDR and LCV to satisfy safety concerns and accelerate the verification of the integrity of optical fiber links, before the application of high Raman laser powered light sources to a fiber link. A system using only one receiver per node is also disclosed.