Specialty Optical Fibers Handbook

It was demonstrated that metal-coated fibers fabricated by the ‘‘freezing’’

technique were indeed hermetically sealed. It means that because of the absence

of water vapor under the metal, the fiber strength can be twice as high as that of

polymer-coated fibers (5.5 GPa) [11]. This value for metal-coated fibers ap-

proaches the glass strength in liquid nitrogen (14 GPa). Fatigue parameter n

in this case will be also high (>100), as compared to n  20 for polymer-coated

fibers. Carbon-coated fibers also demonstrate such a high fatigue parameter but

cannot reach such a high strength because of cracking of the brittle carbon

coating during the tests at high elongation (approximately >5%) [12].

Unfortunately, the freezing method of the metal-coating