Fiber optic cable and core

Abstract From the Canadian patent

A cable adapted for well logging has an optical fiber core in which the optical fibers are protected from moisture and non-uniform stresses by first wrapping the fibers in a helical spiral around a solid soft, deformable core material and then blanketing them with more of the same. Next the blanketed core is closely and tightly wound with several overlapping layers of a metallic tape jacket. The jacket buffers radial loads applied by other portions of the cable and forms a barrier against moisture penetration. The soft core and blanket have properties close to a liquid so that only uniform essentially hydrostatic stresses are transmitted to the optical fibers.