Abstract
Coherence properties of the light from optical fibers are presented. These properties hitherto have been neglected in almost all cases in practice, and applications of optical fibers have been restricted only to incoherent optical systems. On the contrary their applications in interferometry are presented in this paper. As a particular case of two-beam interference, two fibers are employed for measurement of the degree of coherence of light and this principle is extended further to three and four fibers arrangements. On account of the flexibility of fibers, these provide very convenient methods for the observation of coherence. Other uses of optical fibers as coherent optical elements are briefly stated.