Investigation of four-wave mixing 6.4-μm core-diameter fiber with 520–610-nm pump light is used to develop a new technique for characterizing the refractive-index profiles of non-step-index fibers. Deviation from the step-index profile is measured. Small variations in the refractive index between different segments of the same commercial fiber is measured with a sensitivity of 0.0001.
© 1997 Optical Society of America
A. Sharma, R. Posey, L. Phillips, T. George, and P. Ruffin, "Four-wave mixing in non-step-index optical fibers: a sensitive technique for measurement of refractive-index profiles," Opt. Lett. 22, 1311-1313 (1997)