For high speed long transmission network a mode division multiplexing (MDM) based free space optics optical code division multiple access design has been reported. With zero cross-correlation as well as highest autocorrelation properties a code namely zero cross-correlation has been employed to secure the network considering distinct atmospheric conditions. The obtained simulation results indicate that the maximum 75 km transmission range is achieved as well as traffic rate of 35Gbps is obtained for the proposed approach. The comparison of proposed design with existing ones indicates its fine performance.