Study of using different colors of fluorescent fibers as optical antennas in white LED based-visible light communications.

A fluorescent fiber can be used as an optical antenna in visible light communication (VLC) for simultaneous optical filtering and light concentration and therefore to build a compact receiver. Since its light concentration principle is based on fluorescence, it can exceed the étendue limit and achieve both a high concentration gain and a wide field-of-view (FOV). In addition, because the photoluminescence (PL) lifetime of the fluorophore is typically only several nanoseconds, it can support high-speed data transmissions. When a fluorescent fiber antenna is used in a white light-emitting diode (LED)-based VLC system, the transmission performance highly depends on how the absorption and emission spectra of the fluorophore are associated with both the spectrum of the LED and the responsivity of the silicon photodetector. In this paper, we analyze the performance of several different commercially available fluorescent fibers. We show that, when the data rate is low or the transmission distance is long, since the light emitted from a red fluorescent fiber is associated with high silicon responsivities, it can result in high signal-to-noise ratios (SNRs) at the receiver output and therefore lead to low transmission error rates. In contrast, when the data rate is high or the transmission distance is relatively short, the bandwidth dominates the overall performance and consequently the green fluorescent fiber has better performance since it only absorbs the light emitted from the blue LED rather than the light emitted from the yellow phosphor.