Evaluation of Fiber-Bundle Based Transmitter Configurations With Alignment Control Algorithm for Mobile FSO Nodes

A fiber-bundle approach for beam steering at the transmitter was recently proposed and investigated that allowed tracking of the receiver without the use of mechanical devices for mobile free-spaced optical (FSO) platforms experiencing misalignment due to movement and atmospheric turbulence. This paper investigates different transmitter configurations along with a general pointing, acquisition and tracking (PAT) algorithm on key parameters including power availability at the receiver, switching time, link recapturing time, and coverage area at the receiver plane. The alignment control algorithm with different ways to track receiver is also evaluated on these key parameters. The algorithm performance versus transmitted power, switching time and the threshold power for beam steering was examined. The investigation finds that a combination of switching combined with splitting of the light between fibers is a suitable solution to provide the best trade-off between link up time and the coverage area at the receiver, and thus is a good general purpose design choice, and the optical tracking system with target location information demands fewer efforts to recover and maintain the dynamic link than the one without the awareness of the receiver location information.