A peak in attenuation in optical fibers caused by contamination from hydroxyl (OH) ions that are residuals of the manufacturing process. Water peak causes wavelength attenuation and pulse dispersion in the general regions of 950 nm, 1380 nm and 2730 nm. Low-water-peak fiber (LWPF) and zerowater-peak fiber (ZWPF) resolves water peak issues in the 1380 region (1383 nm), thereby opening the entire spectrum from 1260 to 1625 nm for high-performance optical transmission technologies employing coarse wavelength division multiplexing (CWDM). See also attenuation, CWDM, hydroxyl, LWPF, pulse dispersion, wavelength, and ZWPF.