A method of configuring an optical link with an optimized spectral efficiency and bit rate is provided. The method includes obtaining, by a controller of an optical network, a baseline configuration that includes a traffic mode that uses a predetermined channel spacing of a plurality of channels in a frequency spectrum. The plurality of channels are used for transmitting optical signals on an optical link in the optical network. The method further includes selecting three contiguous channels that include a center channel and two adjacent channels and while maintaining a performance parameter above or equal to a threshold value, moving the adjacent channels closer to the center channel and varying at least one transmission parameter, thereby reducing a spacing of the center channel. As such, a spectral frequency map is generated in which the channel spacing is reduced and an optical link is configured based on the spectral frequency map.