An investigation of the coherence of the field radiated from a multimodal optical fiber

The paper deals with an experimental study of the influence of a multimode optical fiber on the coherence of laser radiation. It is shown that the spatial coherence factor in the transmission diagram cross section is generally above 0.9 at fiber lengths in excess of 200 m. The temporal coherence factor of gas-laser radiation after passage through a 230-m fiber is approximately 0.64. The possible formation of interference patterns in the form of regular bands in the case of superposed transmission diagrams of two different fibers with length differences of several hundred meters is demonstrated.