B.S.T.J. brief: Reduction of the 1.38-μm water peak in optical fibers by deuterium-hydrogen exchange

Absorption due to the 1.38-μm overtone of the OH⁻ vibration in silica has long been an obstacle to low-loss propagation in optical fibers at wavelengths near the dispersion minimum. The corresponding absorption spectrum of OD⁻ in silica, however, has a window in this region. A deuterated fiber with OD⁻ content comparable to that of OH⁻ in preaent-day hydrogenated fibers would have a window between 1.0 and 1.65 pm with essentially no added loes due to water.