FOTP-67 Procedure for Assessing High Temperature Exposure Effects on Optical Characteristics of Optical Fibers
|Publication Date:||1 July 1996|
This test procedure describes a method for the determination, in an accelerated manner, of the effects of temperature on the optical characteristics of optical fibers. It is intended to assess the ability of an optical fiber to withstand prolonged exposure to elevated temperature. The performance of the fiber during and after exposure may be evaluated by performing specific optical tests.
The specification of this procedure in conjunction with defined failure criteria presupposes that the failure criteria selected to evaluate the property or properties being measured as a function of exposure temperature and duration can be shown to relate to the intended use of the fiber. At the time this document was prepared, no proven model existed for the prediction of the lifetime performance of fiber deployed in field applications using data generated through high temperature exposure.
Optical fibers exposed to high temperatures may be subject to many types of changes. The severity of the exposures in both time and temperature determines the type and extent of change. An optical property may not necessarily be degraded by temperature exposure or by the duration of such exposure, but may remain unchanged or even improve. A typical indication of damage resulting from such exposure is an excessive temporary or permanent change in an optical characteristic, such as transmittance. The degree of change observed will depend on the property measured. Different properties may not change at the same rate, and the rate and direction of change may not be constant over time and temperature.
The effects of exposure may be quite variable, especially when specimens are exposed for long time intervals. Reproducibility is affected by the temperature control tolerance, the period of exposure, and the aging characteristics of the coating(s), among other factors. Errors in exposure may have cumulative effects over time.
This test is destructive; the fiber specimens are not expected to remain usable after completion of the test.