Research on high-speed transmission characteristics of the BGA ceramic substrate employed in multi-channel optical transmitter module

In this paper, the high-speed electrical transmission characteristics of the ceramic substrate employed in multi-channel optical transmitter module and the factors that affect its electrical characteristics encompassing equivalent model of BGA balls below ceramic substrate, roughness of metal material-Au, width tolerances of transmission lines on surface of ceramic substrate and length of bonding wire between modulator and driver chips were analyzed and studied. According to the inconformity between simulation and test results, an optimized simulation model was proposed and verified to estimate test high-speed performance of the ceramic substrate better. The 3-dB bandwidth of transmission lines on the ceramic substrate is nearly 35GHz which demonstrates that the optical transmitter module based on the ceramic substrate has great potential to support successfully transmission exceeding 25 Gb/s.