A comparative study is presented between NRZ and 4-PAM to investigate the feasibility of Gigabit transmission in automotive optical networks. The system utilizes a SI-PCS fiber and an 850 nm VCSEL as transmitter. Laser driver and receiver are realized with discrete transistors at board level. Eye diagram measurements reveal that 4-PAM outperforms NRZ using 1m and 6m of fiber. Bitrates of 2 Gb/s are achieved at a BER ≤ 100000. Covering longer distances shows that SI-PCS introduces severe dispersion. Therefore, GI-PCS fiber is suggested as optical link for future automotive networks
