title: Rayleigh backscattering from the fundamental mode in multimode optical fibers.
abstract: Rayleigh backscattering produced by an incident fundamental mode in a multimode optical fiber is analyzed using a diffraction technique, with a full set of backward-propagating modes being taken into consideration. Explicit formulas are derived for mode excitation efficiency via radial distributions of the mode fields, and it is proved that only half-azimuthal modes are backscattered by the incident wave of a fixed polarization. Advanced analytical expressions are developed for fibers with a quadratic refractive-index profile, and mode groups of even numbers, composed of modes with equal propagation constants, are stated to be excited with equal efficiencies.
authors.forename: M A
authors.initials: MA
authors.lastname: Bisyarin
authors.forename: O I
authors.initials: OI
authors.lastname: Kotov
authors.forename: A H
authors.initials: AH
authors.lastname: Hartog
authors.forename: L B
authors.initials: LB
authors.lastname: Liokumovich
authors.forename: N A
authors.initials: NA
authors.lastname: Ushakov