In this paper, 1.28 Tbps (32 × 40 Gbps) high-capacity DWDM-FSO link has been investigated for performance enhancement using coherent detection and digital signal processing (DSP). The DP-16QAM-modulated proposed DWDM-FSO link has been analyzed for both adverse weather and turbulent atmospheric conditions. It is observed that when link is subjected to strong turbulence along with adverse weather conditions, the DSP-aided coherent DWDM-FSO receiver achieves target bit error rate (BER) of 10⁻⁴ at signal-to-noise ratio (SNR) of 36.4 dB, while for similar conditions, the SNR requirements for IM/DD-based DWDM-FSO link shoots by 12.8 dB to 49.2 dB. Also, in terms of operational link range, the proposed link even under strong turbulent conditions serves 1.88 km, whereas IM/DD link was restricted to mere 1.12 km for target of BER of 10⁻⁴, thus producing a decent range increment of 760 m. The proposed link has been designed and investigated using OptiSystem™ 14.2.

中文翻译：

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使用数字信号处理提高大容量相干DWDM自由空间光通信链路的性能

本文研究了1.28 Tbps（32×40 Gbps）大容量DWDM-FSO链路，以利用相干检测和数字信号处理（DSP）来提高性能。已对DP-16QAM调制的建议DWDM-FSO链路进行了恶劣天气和大气湍流条件分析。可以观察到，当链路经受强湍流以及不利的天气条件时，DSP辅助相干DWDM-FSO接收机的目标比特误码率（BER）为10 ^-4在36.4 dB的信噪比（SNR）下，而在类似条件下，基于IM / DD的DWDM-FSO链路的SNR要求则提高了12.8 dB至49.2 dB。此外，就操作链路范围而言，即使在强湍流条件下，建议的链路也可服务1.88 km，而对于BER为10 ^-4的目标，IM / DD链路仅限于1.12 km ，从而产生了760 m的体面距离增量。建议的链接已使用OptiSystem™14.2设计和研究。