Analysis and simulation of a fiber bundle method for creating a partially spatially coherent beam

摘要

A fiber bundle arrangement has been proposed in the literature to produce a partially spatially coherent beam. The bundle contains fibers of random lengths and the source has limited temporal coherence. The analytical expression for the autocorrelation function of the bundle pupil is derived, which defines the behavior of the beam as it propagates. Simulation results are used to verify the analytic theory. The far-field irradiance pattern for the bundle arrangement is addressed analytically and through wave optics simulation. Averaging the irradiance pattern for a number of simulation realizations was shown to converge to the analytic result. The process of averaging over a small band of source wavelengths is developed and is shown to result in a spatially partially coherent beam. Simulation results again compared favorably with the analytic theory.