Specialty Optical Fibers Handbook

Apart from the reversible microbending loss, irreversible loss growth occurs

in metal-coated fibers in the temperature range 300–1000 8C. Such effects have

been detected but have not been investigated thoroughly [41, 45]. It is known

that the irreversible loss strongly depends on the core and cladding chemical

composition and increase as a result of hydrogen penetration from outside [31].

15.6 SUMMARY

During the last 20 years of research on metal-coated fiber technology, many

fundamental works have been performed aimed at obtaining coatings with genu-

ine hermeticity. With such coatings, the static fatigue phenomena can be minim-

ized and the fiber strength can be close to the theoretical limit for silica glass.

Although some problems remain unsolved, ...