In a ring network comprising a plurality of nodes and a 16 channel coarse
wavelength-division multiplexing (CWDM) plan, a technique is disclosed
for adding and dropping channels that reduces the maximum attenuation
loss that any channel encounters--thereby enabling longer rings to be
constructed without using optical amplifiers in the ring. The 16 channels
are typically distributed between the wavelengths 1310 1610 nm with 20 nm
separation between channels. It is obscured that glass fibers have
gradually decreasing loss at longer wavelengths in this band. The network
includes a hub and several nodes that are interconnected by optical
fibers in a ring configuration, where distance from the hub is the
minimum value measure in either the clockwise or counterclockwise
direction. Channels are assigned to the various nodes based on their
wavelength. The channels whose wavelengths are near 1310 nm are assigned
to nodes that are progressively closer to the hub.