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.