Temporal coherence of laser radiation transmitted by a multimode waveguide

The results are given of a theoretical calculation and of experimental investigations of the temporal correlation function of multifrequency laser radiation transmitted by multimode fiber waveguides of up to 550 m in length. The results indicate that the periodic dependence of the correlation function $\vert\gamma(\tau)\vert$ on the delay time $\tau$ is retained under multimode conditions. An increase in the fiber length broadens the dependence $\vert\gamma(\tau)\vert$.