In this study, we explore the transmission of a high-speed 10Gbps optical signal over a hybrid Single-Mode Fiber (SMF) and Multi-Mode Fiber (MMF) system using Optisystem. The optical signal is initially transmitted over 5-20 kilometers of an SMF, ensuring minimal dispersion and loss while maintaining signal integrity. Following the SMF transmission, the signal is coupled into an MMF, which operates in the LP01 mode. The MMF generates 16 distinct modes, each carrying the optical field of the transmitted signal. The simulation outcomes demonstrate that the hybrid system can sustain high signal quality and low BER across different fiber spans, showing resilience against modal dispersion and attenuation. By optimizing parameters like laser wavelength, modulation format, and receiver sensitivity, we achieved efficient signal transmission suitable for high-speed applications. This research underscores the potential of hybrid SMF-MMF systems to meet the growing demand for high-bandwidth communication in contemporary optical networks, especially where integrating different fiber types can offer a more adaptable and scalable solution. In addition, this multimode transmission approach aims to leverage the capacity of MMFs to handle multiple modes. Future work will investigate advanced modulation techniques and the effects of environmental factors on system performance to further improve the reliability and efficiency of hybrid optical networks.