Specialty Optical Fibers Handbook

equal-diameter sapphire and silica fibers. There has been only limited strength

data taken on the optical SC sapphire fibers. Wu et al. [39] have measured

110-mm diameter LHPG fiber under tension. Their measurements yielded failure

strains between 1.20 and 1.85%. These are measurements on only two samples,

so their statistics are quite limited. Photran, Inc. (formerly Saphikon) claims that

its 325 mm diameter fiber can be bent into a 60-mm loop. Jundt et al. [35]

indicate that their 150-mm diameter LHPG fiber can be bent to a 4-mm radius.

13.6 HOLLOW-CORE WAVEGUIDES

The first optical frequency hollow waveguides were similar in design to micro-

wave guides. Garmire et al. [40] made a simple rectangular waveguide using

aluminum strips spaced 0.5 mm