The evolution of optical communications systems from long fibers to robust wireless system has led to the idea of connecting two satellites using an optical wireless link. The rapid developments in satellite communication point to the possibilities of satellite networks as a method for them to communicate with each other. The optical wireless communication (OWC) enables the information exchange between satellites at higher speed and also a satellite can act as a relay between two satellites or between a satellite and ground base station. Light signal of high frequency is used as a carrier for the optical link between satellites and lasers are commonly used as a source of light. One of the primary reasons for preferring OWC over RF link is high data rate with acceptable bit error rate (BER). The communication between two lower earth orbit (LEO) satellites is studied under this research work. The quality factor (Q-factor) or BER is used as a key metric to analyze the performance of the inter-satellite link (ISL). This work presents the performance enhancement of the system by using multiple antennas and advanced modulation techniques.