Specialty Optical Fibers Handbook

loss in commercial fibers had been obvious for more than 2 decades, the enor-

mous technical and commercial challenges of realizing a viable zero-OH manu-

facturing fostered a belief in its impracticality. Today ZWP performance

(L

1383nm

< 0:31 dB=km) can be guaranteed at essentially no additional cost to a

carrier.

5.4.1 Pure Silica Core Fiber

The design of pure silica core fiber seeks to minimize Rayleigh scattering

losses due to nanoscopic fluctuations in the index of refraction (determined by

either the glass density or the chemical composition). Average loss of 0.168 dB/

km is commercially obtained at 1550 nm, while the loss minimum near 1580 nm

is a few thousandths lower still. This is achieved by eliminating germania as the

dopant to create the ...