Spatial Coherence Properties Of Light From Optical Fibers

Abstract

The mutual intensity of the optical field in the Fraunhofer diffraction region from the end of an optical fiber is analyzed theoretically by using a fiber-end source model. Tn this source model, the optical field at the end of the fiber is expressed as a sum of independent plane waves with random directions and phases since the guided modes propagating through an optical fiber may be regarded as a stochastic process. It is found that the spatial coherence property of the optical field in the diffraction region is not homogeneous but quasihomogeneous in a statistical sense. This property is discussed in connection with the V number of the fiber and in comparison with that of the optical field, obeying the van Cittert-Zernike theorem, produced by the incoherent source.