Specialty Optical Fibers Handbook

if it may be theoretically capable of 35 dB or better. When assembling equip-

ment to make these measurements, you should consider that most ER or H-

parameter rigs put together from nonoptimized components will struggle to

measure better than about 25 dB. Achieving 30 dB or higher requires either

a great deal of luck or the hand selection of top-quality components.

8.7 MECHANICAL AND LIFETIME PROPERTIES

8.7.1 Strength Paradox I: Fragile Preforms Make

Exceptionally Strong Fibers

In all stress-birefringent fibers, it is the preform fabrication stage that pro-

vides the greatest challenge to process yields—particularly for the bowtie and

elliptical jacket fibers. As stressed structures formed from brittle materials, both

bowtie and elliptical jacket ...