Improvements in free-space optics (FSO) networks have been driven by a growing need for higher data transmission speeds, broader channel capacities, and spectrally efficient communication lines with sophisticated modulation techniques. This paper details an FSO transmission approach that employs an eight-channel wavelength division multiplexing (WDM) scheme, combining dual-polarization amplitude modulation (DP-16-QAM) with spectrally efficient techniques to enable each channel to transmit at 256 Gbps. The integration adapts system performance using digital signal processing and signal degradation compensation techniques tailored for turbulence, atmospheric attenuation, and channel fading. To address this problem, an enhancement at the receiver side is proposed to be integrated in the form of a high-order Gaussian low-pass filter positioned before the signal enters the DSP to alleviate the effects of the atmosphere further. This approach helps to mitigate attenuation effects and enables more accurate and faster signal processing. We demonstrate, through numerical simulations, that 2.048 Tbps can be effectively transmitted over FSO connection ranges from 2.18 kilometers up to 111 kilometers, achieving acceptable bit error rates under varying meteorological conditions. We demonstrate the system's higher bit rate and range by comparing its performance to previous efforts. The proposed technology can be implemented to guarantee dependable high-speed data transfers for both front and backhaul networks, even under the most challenging meteorological conditions. Additionally, this system's capacity and resilience to harsh weather conditions make it suitable for emerging systems, such as the Internet of Things (IoT) and sixth-generation (6G) technology, ensuring seamless integration without significant modifications................ Keywords................. Free space optics (FSO), Atmospheric attenuation, Wavelength multiplexing (WDM), Dual-polarization multiplexing (DPM), Quadrature amplitude modulation (QAM), Bit error rate (BER).