This paper proposes an enhancement of semiconductor optical amplifier (SOA)-based scintillation mitigation by polarization shift on-off keying (PS-OOK) transmission in free-space optical (FSO) communication. The scintillation effect is a critical issue in a vertical FSO link. The issue of the extinction ratio (ER) degradation of the received OOK signal caused by the high dynamic gain frequency of the SOA limits the performance of the turbulence-induced scintillation effect mitigation using a gain-saturated and polarization-independent SOA. Therefore, a PS-OOK signal, which has the characteristics of orthogonal polarization of bits “1” and “0,” is transmitted at the transmitter end and a linear polarizer is deployed after the gain saturated SOA at the receiver end. Based on the polarization orthogonality of PS-OOK, the performance of the scintillation-effect suppression is significantly improved by the mitigation of the ER degradation by the blocking of the polarization of bit “0” of the received optical PS-OOK signal using the linear polarizer. The proposed scheme is experimentally verified utilizing the Mach-Zehnder modulator (MZM)-based fading simulator accommodated various turbulence channels. The experimental results illustrate that the scintillation effect is effectively suppressed by the proposed technique compared to the SOA-based conventional single-polarized OOK detection and balanced PS-OOK detection.

中文翻译：

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在 FSO 通信中通过 PS-OOK 传输增强基于 SOA 的闪烁减轻

本文提出了在自由空间光 (FSO) 通信中通过偏振位移开关键控 (PS-OOK) 传输增强基于半导体光放大器 (SOA) 的闪烁减轻。闪烁效应是垂直 FSO 链路中的一个关键问题。SOA 的高动态增益频率导致接收到的 OOK 信号的消光比 (ER) 退化问题限制了使用增益饱和且与极化无关的 SOA 来减轻湍流引起的闪烁效应的性能。因此，发送端发送具有比特“1”和“0”正交极化特性的PS-OOK信号，接收端在增益饱和SOA后部署线偏振器。基于PS-OOK的偏振正交性，通过使用线性偏振器阻止接收到的光学 PS-OOK 信号的位“0”的偏振来减轻 ER 退化，显着提高了闪烁效应抑制的性能。所提出的方案使用基于 Mach-Zehnder 调制器 (MZM) 的衰落模拟器进行了实验验证，该模拟器适应各种湍流通道。实验结果表明，与基于SOA的传统单极化OOK检测和平衡PS-OOK检测相比，所提出的技术有效抑制了闪烁效应。所提出的方案使用基于 Mach-Zehnder 调制器 (MZM) 的衰落模拟器进行了实验验证，该模拟器适应各种湍流通道。实验结果表明，与基于SOA的传统单极化OOK检测和平衡PS-OOK检测相比，所提出的技术有效抑制了闪烁效应。所提出的方案使用基于 Mach-Zehnder 调制器 (MZM) 的衰落模拟器进行了实验验证，该模拟器适应各种湍流通道。实验结果表明，与基于SOA的传统单极化OOK检测和平衡PS-OOK检测相比，所提出的技术有效抑制了闪烁效应。