Light leakage in optical fibers: Experimental results, modeling and the consequences for solar concentrators

Optical fibers used to transport sunlight exhibit considerable light leakage within their nominal numerical aperture. Of particular interest in the design and diagnosis of solar fiber-optic concentrators is the dependence of this leakage on: (a) incidence angle, (b) the optical properties of the core and the cladding, and (c) fiber length. We present measurements of fiber angular transmission, along with a theoretical model. The implications for solar fiber-optic concentrators are also assessed.