Photonic materials are used for electronic applications in recent days, therefore this research grows exponentially. However, fiber is the major component and acts as the medium for photonic applications. In this paper, the fiber is designed by analyzing its structure. To design and simulate the performance of spatial-division-multiplexing (SDM) transmissionis verified. The transmission link over the C+L band with 7-mode is evaluated using trench-assisted graded-indexfiber(TA-GIF). To enhance the transmission capacity of conventional single-mode optical fiber links, this work introduces an intensity-modulation and direct-detection (IM-DD) SDM scheme. The spatial-multiplexing is achieved through seven linearly-polarized (LP) mode groups (LP₀₁, LP₁₁, LP₀₂, LP₂₁, LP₃₁, LP₁₂, and LP₄₁) for transmitting seven distinct 10 Gbps/data channels/mode. The minimum bit-error-rates (BER), maximum Q-factors of the individual spatially-multiplexed data channels over a link length of 30 km have been evaluated successfully using an experimental link set-up. It is found that four modes are successively carrying the data for transmission. However, some of them through generated but can not carry up to 30 km instead of 15 km.