Mode Coupling Effects in Graded-index Optical Fibers.

Mode coupling theory is applied to the study of multimode optical fibers with graded-index cores. For coupling caused by random bends in the waveguide axis, the results predict the dependence of the induced losses on the fiber's characteristics. The impulse response is determined for fibers with random bends having several different power spectra. The results are used to predict the transmitted power, the delay time, and the rms pulse width in fibers with graded-index cores.