### Background and Motivation  
With the growing demand for high-speed, low-latency communication in the era of 5G and beyond, and the huge capital expenditures associated with public works (such as trench digging and site restoration) limiting the widespread installation of optical fiber infrastructure, FSO communication has emerged as a potent technology poised to meet these demands [3]. FSO communication, which involves the transmission of data through the atmosphere using optical beam, offers an attractive alternative to traditional RF communication due to its potential for low latency, noise immunity, electromagnetic interference immunity, spatial reusability, ease of deployment, being license free, high security, reduced spectrum congestion, and the capability to deliver transmissions at extremely high data rates between two terminals [4; 5], whether they are just a few meters apart or separated by thousands of kilometers (long operational range) [6]. FSO systems are especially advantageous for line-of-sight (LoS) communication, bridging gaps where traditional fiber optics or RF systems may not be feasible. For instance, FSO systems utilize narrow laser beams with directional properties. This spatial confinement allows for a high degree of spatial reuse and makes eavesdropping difficult, inherently enhancing security. Utilizing light as the carrier in FSO communications ensures immunity to electromagnetic interference. Additionally, FSO systems are easy to deploy and can be reinstalled without incurring the costs associated with dedicated fiber optic connections. Moreover, the frequency used by FSO technology exceeds 300 GHz, which is unlicensed globally, thus eliminating the need for license fees [1; 2; 7]. Frequencies in FSO communications are significantly higher than those in RF communications. Consequently, FSO communications can achieve much higher data rates compared to RF communications, and they require antennas that take up less space. Additionally, the coherence of laser light in FSO links can decrease geometrical loss, allowing the transmission of high data rates over long distances [7]. Figure 1 illustrates various FSO applications along with their respective communication ranges. The capability to transmit data over long distances without the need for physical infrastructure makes FSO a suitable candidate for supporting next-generation wireless networks, including 5G and beyond [8]. In this context, the absence of a need for optical fibers between communication nodes allows for flexible application across various use cases and high-speed applications including unmanned aerial vehicles (UAVs), intra- and inter-datacenter connections, inter-building links, high-speed trains, 5G fronthaul and backhaul for wireless cellular networks, indoor and outdoor local- and wide-area networks, metropolitan area network extensions, urban connectivity, last-mile connectivity, inter-chip connectivity, fiber backup, satellite communications, deep-space communications, underwater communication, disaster recovery, video surveillance, and redundant link [2; 9; 10]. Additionally, it is regarded as a promising solution for addressing the significant traffic demands of sixth-generation (6G) systems [11; 12]. These use cases can be classified into two main categories, terrestrial and outer space FSO communications, as illustrated in Figure 2. Given its benefits, FSO is being explored as a solution for last-mile connectivity in situations where fiber deployment is challenging and RF systems fall short of meeting bandwidth needs. Additionally, these advantages position FSO as a highly promising solution for space communications. In this context, by leveraging its strengths, FSO can address many of the challenges associated with traditional communication methods, providing a more efficient and reliable means of data transmission between spacecraft, satellites, and ground stations [13].