Semiconductor optical amplifier-assisted optical wireless links: The effect of noise and turbulence

We present an analytical framework for estimating the benefits that arise from the utilization of semiconductor optical amplifiers (SOA)s at fade impaired outdoor optical wireless systems. We first investigate the impact of fading on both the signal optical power and the amplified spontaneous emission, and derive analytical relations that accurately associate the system bit-error-rate (BER) with the channel state. We then utilize the analytical relations to assess the performance of the amplified optical signal under moderate-to-strong fading and demonstrate that the sensitivity improvement, which is expected by the amplification process, improves the first- and second-order signal-to-noise ratio statistics at the electronic receiver. Our results show that the average BER and average fade duration can all be drastically reduced by the incorporation of the SOA, provided that the link length remains within reasonable limits that are dictated by the channel statistics.