## 1 Introduction  
In recent years, laser communication has emerged as a key enabler of space-based high-speed, high-bandwidth, and low-latency communication. Compared with traditional RF systems, laser links offer superior spectral efficiency and robustness, particularly in deep-space exploration and satellite networking applications [1; 2; 3; 4]. However, during Sun outage events--when the Sun, satellite, and ground terminal become nearly collinear--the intense solar background radiation couples into the optical link, drastically reducing the signal-to-noise ratio and potentially interrupting communication [5; 6]. To address Sun outages, various mitigation strategies have been explored globally. For instance, [PERSON] et al. (2022) developed a geometrical Sun outage prediction model for Earth-orbiting satellites, enabling easier prediction of spacecraft solar outage over ground station antennas using state vector or TLE information [7]. [PERSON] et al. (2024) introduced an all-optical approach utilizing an optical parametric amplification (OPA) processor to suppress the impact of Sun outages in laser satellite communication systems [8]. Their optimized OPA processor demonstrated a significant improvement in signal quality during solar interference events. Additionally, [PERSON] et al. (2024) proposed a Local Pre-Rerouting Algorithm (LPRA) for inter-satellite links in low Earth-orbit satellite networks, aiming to reroute services before Sun outages occur, thereby enhancing network resilience [9]. Furthermore, some countries have conducted in-orbit experiments to investigate Sun outage effects [10; 11; 12], including China's Tianwen-1 mission, ESA's Laser Communication Terminal (LCT) project, and NASA's Laser Communications Relay Demonstration (LCRD). These studies indicate that solar noise has minimal impact on communication when the Sun-Earth-Probe (SEP) angle exceeds 3\({}^{\circ}\). From a methodological perspective, existing anti-interference approaches can be categorized as follows: Array detector systems [13] employ spatial diversity to enhance signal-to-noise ratio, while adaptive phase correction [14] and simplified modulation schemes [15] optimize signal recovery in hostile channels. While the former dominates in-orbit applications, the latter is critical for ground validation systems where realistic solar interference must be replicated without distorting the co-propagating signal. Although prior research has confirmed general Sun outage effects under wide-angle conditions, there remains a lack of high-precision and repeatable ground-based verification platforms for evaluating the anti-interference performance of terminals within narrow fields of view, such as \(\pm 3^{\circ}\). Most existing studies rely on costly in-orbit resources with limited controllability and poor repeatability, making them unsuitable for early-stage engineering validation. Moreover, conventional solar simulators are mostly static simulators that only simulate the spectral energy distribution of solar radiation [16; 17; 18; 19]. The solar simulator discussed in this paper is designed for solar transit scenarios, which is a dynamic simulator integrating relative attitude changes, a certain field of view range, spectral characteristics, and specific irradiance energy. To address these gaps, this paper presents the design and implementation of a high-consistency solar radiation simulation system targeting the 1540-1560 nm communication band. The system features high spectral fidelity, superior irradiance uniformity, and wide range power adjustability, and for the first time integrates signal beam co-path output and stray light suppression mechanisms to reconstruct realistic Sun outage interference scenarios on the ground. The platform supports quantitative anti-jamming evaluation of optical terminals over a \(\pm 3^{\circ}\) field of view.