## 1 Introduction  
For decades, the growing demand for faster and more efficient data transmission has driven significant advancements in free-space optical communication (FSOC) [1, 2, 3]. FSOC has expanded into multiple application domains, such as satellite laser communication [4], satellite ground laser communication [5], and unmanned aerial vehicle communication [6], etc. However, atmospheric turbulence can severely degrade beam transmission by distorting both the power distribution and wavefront shape, affecting the communication efficiency of laser-based systems [7, 8, 9]. In particular, when propagating through turbulent channels, the Gaussian beam (GB) is highly susceptible to intensity scintillation [10]. In FSOC, down-link systems leverage adaptive optics (AO) to mitigate atmospheric turbulence effectively, due to their optical path enabling precise ground-based wavefrontcorrection [11]. The up-link systems face inherent limitations. Because the point-ahead angle often exceeds the isoplanatic angle, which results in anisoplanatic effects. These effects render AO precorrection ineffective [12]. While laser guide stars enhance AO pre-correction capabilities, their performance is constrained by the limited correction field imposed by isoplanatic angle restrictions, inherent luminance limitations, and reduced sensitivity to oblique wavefront aberrations [13]. The multi-guide-star configurations have been proposed to address these issues, but such approaches introduce higher system complexity and significant cost challenges. Spatial diversity technology has also been used to suppress optical intensity fluctuations [14], but it requires complex hardware and signal processing algorithms. Therefore, it is necessary to develop efficient methods to mitigate intensity scintillation, which remains a critical and challenge for up-link FSOC systems.  
The optical pin-like beam (OPB), which is first proposed by [PERSON] et al. in 2019 [15], represents a novel beam profile with unique propagation characteristics. It is proven that the OPB exhibits remarkable turbulence suppression capabilities while maintaining stable propagation over kilometer-scale distances [16]. Beyond optical communications [17; 18; 19; 20], OPBs have found applications in diverse fields, including optical trapping and particle manipulation [21; 22], as well as nonlinear optics [23]. Previous research has primarily focused on analyzing far-field intensity distributions and energy fluctuations of OPB, while the application on scintillation suppression has not enough. Although a few studies have explored the impact of OPB on intensity scintillation [24], their scope has been limited to a single OPB configuration. Therefore, the correlation between beam parameters and scintillation characteristics has not been explored. In this study, we systematically investigate the scintillation suppression characteristics of OPB in atmospheric turbulence through theoretical derivation and numerical simulations. Based on the wave equation, an analytical expression for the focal length of OPB has been derived. This formula contributes to the design of a set of OPBs with identical focal lengths and different beam parameters. Through spatial transmission simulations, we analyze the propagation characteristics, scintillation index (SI), and average received power (ARP) stability in different turbulent channels. The results indicate that optimized OPB significantly suppress turbulence-induced intensity scintillation, a capability particularly advantageous in up-link communication scenarios. This suppression capability effectively contributes to the stable transmission of the beam in FSOC.