Throughput and coupling in optical fibers

Optical throughput, namely the product of area times subtending solid, is a useful concept in calculations of light coupling to optical fibers. It is invariant through an optical system, thus providing a simple and elegant way to derive the maximum coupling efficiency between a light source and a fiber, regardless of intervening optics. Because throughput is proportional to the number of modes supported by an optical structure, it also yields the distribution of modal power within a fiber.In this paper, we illustrate applications of throughput by calculating light coupling into fibers and mode distribution within.