REFRACTIVE INDEX OF OPTICAL FIBRES

摘要

A method is disclosed for determining the refractive index profile of an optical fiber (12) wherein light from an intense optical source (16) is focused at the bare fiber end portion of the test fiber. A small amount of light will be coupled into the optical fiber where for the short length of uncoated fiber only cladding modes are excited. The index of refraction is determined directly by analyzing the intensity distribution emitted from the optical fiber (12) with a lens system (24) having a limited numerical aperture (26).