Theoretical and experimental investigations are described for determining the transmission characteristics of a multimode fiber with microbending for coherent and partially coherent illumination. The measured values of the average excess power loss are shown to be in close agreement with the theory. Also, an estimate of the excess transient loss due to mode coupling is found to be in good agreement with previously published data. Mode–mode interference is shown to be the cause of temporal fluctuations in the microbending loss, from which expressions for modal noise and baseband/subcarrier nonlinearity are derived on a statistical basis. For a given overall loss, the results show that many uniformly distributed small amplitude microbends cause much less modal noise and distortion than a few large amplitude microbends.
© 1985 Optical Society of America
Original Manuscript: August 20, 1984
Published: August 1, 1985
Santanu Das, Colin G. Englefield, and Paul A. Goud, "Power loss, modal noise and distortion due to microbending of optical fibers," Appl. Opt. 24, 2323-2334 (1985)