The Telecommunication Industry Association has adopted a document that establishes uniform requirements for the mechanical characteristic fiber curl or latent curvature in uncoated optical fibers.

The TIA has adopted IEC-60793-1-34, Optical Fibers -- Part 1-34: Measurement Methods and Test Procedures -- Fiber Curl, as an American national standard, fiber optic test procedure (FOTP)-111, TIA-455-111-A.

The document is a revision of TIA/EIA-455-111.

Fiber curl has been identified as an important parameter for minimizing the splice loss of optical fibers when using passive alignment fusion splicers or active alignment mass fusion splicers.

Two methods, presented in Annexes A and B respectively, are recognized for the measurement of fiber curl in uncoated optical fibers: method A -- side view microscopy; and method B -- laser beam scattering.

The side view microscopy measures the radius of curvature of an uncoated fiber by determining the amount of deflection that occurs as an unsupported fiber end is rotated about the fiber's axis. The laser beam scattering procedure measures fiber curl in an optical fiber by laser beam scattering.

By knowing the maximum deflection of the fiber and the overhang distance from the fiber fixture to the measurement point, the fiber's radius of curvature can be calculated from a simple circular model, the derivation of which is given in annex C. Both methods are applicable to types A1, A2, A3 and B optical fibers. Method A is the reference test method, used to resolve disputes.

TIA-455-111-A was adopted by TIA FO-4.6 Subcommittee on Optical Fibers and released November 2003.

The TIA is based in Arlington, VA. For more information, visit www.tiaonline.org.