Low-shrink reduced-diameter buffer tubes

摘要

Disclosed is a low-shrink buffer tube having a reduced diameter. The buffer tube provides adequate crush resistance and is suitable for deployments requiring mid-span access.

主权项

1. An optical-fiber buffer tube, comprising:
a polymeric tube defining an annular space; a plurality of optical fibers positioned within the annular space of said polymeric tube; and a thixotropic composition at least partially filling the annular space of said polymeric tube; wherein said optical-fiber buffer tube possesses a buffer-tube filling coefficient of substantially 0.30 or more; wherein said buffer tube exhibits post-extrusion shrinkage (PES) of 0.1 percent or less upon subjecting said optical-fiber buffer tube to post-extrusion-shrinkage testing in accordance with the TMA method in which a specimen of said buffer tube is subjected to the following temperature program: (i) equilibrate at 25° C. for 10 minutes; (ii) ramp to −40° C. at 10° C. per minute; (iii) ramp to 85° C. at a rate of 10° C. per minute; and (iv) ramp to −40° C. at a rate of 10° C. per minute; wherein, upon subjecting said optical-fiber buffer tube to the mid-span testing according to the GR-20-CORE mid-span standard in which at least 14 feet of said buffer tube is exposed to normal outside conditions in which temperature is cycled between −40° C. and 70° C. while stored in a pedestal, said optical fibers possess an average change in optical-fiber attenuation of no more than 0.15 dB at a wavelength of 1550 nanometers; and wherein said buffer tube has permanent deformations of 10 percent or less after sheave testing.