This test method describes procedures to determine the bending loss of uncabled graded-index multimode or single-mode fiber. The applicability to step-index fiber may require different conditions in 3.2 to 3.4, and in 6.5. Various bend radii and numbers of turns can be accommodated.

This test can be used to compare the bend performance of different fibers at various wavelengths. Its purpose is to help characterize fiber performance in bend configurations such as in fiber routing within equipment racks, or bending of excess fiber within splice housings. It may also indicate relative fiber performance affected by cabling curvature lays and in cable routings.

The test is performed on uncabled fiber only, although the results may be useful in predicting fiber performance in cables or pigtails.

Either of two methods (or both) are permitted by the test procedure, as specified in the Detail Specification.

Method A measures the increase in the fiber attenuation due to a change from the straight condition to a bent condition. This is suggested for a smaller number of turns and/or larger bend radii.

Method B measures the total attenuation of the fiber in the bent condition. This is suggested for a larger number of turns and/or smaller bend radii.

If both Method A and Method B are used, an optional calculation can be