Performance enhancement of gain saturated SOA based free space optical link using dual-wavelength transmission

摘要

This paper proposes the dual-wavelength transmission technique for improving the performance of the gain-saturated semiconductor optical amplifier (SOA)-based free-space optical (FSO) communication link. When the gain saturated SOA is used to suppress turbulence-induced scintillation, extinction ratio (ER) degradation effect occurs owing to the high-dynamic gain frequency characteristics for intensity modulation and direct detection (IM/DD) system. The proposed method uses small-spacing dual-wavelength (signal and supplemental wavelengths) transmission to compensate ER degradation by mitigating the gain difference between the bits '1' and '0'. Regarding the supplemental wavelength, continuous wave (CW) with various average powers and differential signal (DS) transmissions are experimentally investigated. The proposed technique is evaluated under various turbulence channel strengths. The experimental results show that the bit-error rate (BER) performance is significantly improved via effective ER degradation compensation and scintillation suppression.