Experimental Investigation of All-Optical Relay-Assisted 10 Gb/s FSO Link Over the Atmospheric Turbulence Channel

This paper presents novel experimental results for a 10 Gb/s triple-hop relay-based all-optical free space optical (FSO) system by employing the amplify-and-forward relaying scheme. We provide a mathematical framework for the end-end signal-to-noise ratio (SNR) and the bit-error rate (BER) performance and confirm that the derived analytical results reasonably match experimental results especially at relatively high SNR. The evaluated BER performances under different atmospheric turbulence regimes (modeled by the Gamma-Gamma distribution) show that the considered relay-assisted FSO system offers a significant performance improvement for weak-to-strong turbulence regimes, even without knowledge of the channel state information. More precisely, at a target BER of 10-5, the proposed scheme offers ~5 and ~4 dB of SNR gains compared to the direct transmission for turbulence strengths Cn2 of 3.8 × 10-10 m-2/3 and 5.4 × 10-12 m-2/3, respectively